THE PSITTACINE EGG
The egg is a very important element in the overall breeding plan, but it is quite often forgotten as people focus on size and color. Eggs can be difficult to get to and breeders worry about excessive handling, infection and disturbing the hen on her nest. These are all very good reasons for being careful when looking in or handling eggs or nestlings. Furthermore, rough handling of the egg can addle / kill the embryo by breaking the two fine lines of chalazae that support the yolk and embryo. The chalazae ensure that which ever way the egg is turned the embryo will face "up". Despite the dangers associated with handling eggs, researchers need to sometimes handle the egg to candle it (determining fertility of egg); measure and weigh it; check it for damage and sometimes open them when the chick is in a certain embryonic stage. The egg can be a fairly good sample of the living conditions, health and diet of the hen parrot or other birds.
A hen who is receiving all of the requisite nutrients, green food, sunlight and fruit will rarely have trouble with egg production. The right mate, plenty of space and exercise, minimal interference with the box, few noisy or argumentative neighbors and the right age to breed, and she is set to go. In other words the usual captive conditions for a healthy productive and friendly parrot. If, however, birds are overcrowded, fed on a seed diet only, provided little if any exposure to natural (or artificial light) sunlight and made to live in dirty and poorly ventilated conditions, one is more likely to experience problems with the health of their birds and eggs.
Hen and egg problems are more common in unmanaged, crowded aviaries where uncontrolled mating of young birds (birds under 10 - 12 months) occur. Hens, under the conditions described, and sometimes even under much better and more controlled conditions will have a greater likelihood for egg binding. Without immediate intervention, the hen will likely die. If she survives, one needs to examine the age of the bird and its overall health, as these birds may well be more susceptible to egg binding or prolapse at a later date.
Continuous breeding can result in changes to the shape and integrity of the egg, as well as physical weaknesses in the hen and potentially difficulties for the embryos and chicks. A hen in tip top condition, favored by plenty of space, an agreeable mate and the right diet will usually produce eggs and progeny with good vigor and fertility if only one to two and sometimes three nests are taken.
A hen preparing to lay eggs needs a good source of calcium, whether that is obtained through cuttlebone, vegetables or powder is inconsequential, as long as she gets enough to produce the eggs for the number of nests that the breeder intends to take each year. The healthy active hen represents the best possible place for viable eggs and offspring to form and ensures (in the majority of cases) that the offspring will be large, healthy and active. Conversely, a hen that is constantly having to fight to keep others from the nest box; struggle for food and is unable to access necessary vitamins, nutrients or cuttlebone, will not only begin to exhibit signs of malnutrition herself, but will probably be unable to transfer the necessary nutrients to the developing yolk and shell (if she is able to produce eggs at all). The egg and embryo, it can be surmised, may be subject to a host of potential problems associated with vitamin / nutrient deficiency, if the egg develops and the embryo survives.
Egg shells should be well developed and oval in form unless a physical problem (abnormality in the oviduct or obstruction in the isthmus or uterus) leads to strange layering of the albumen or shell. Occasionally a vaccination or a vaccination given late in life may lead to anomalies in egg shape. Very infrequently, round eggs will be laid that are smaller than the average. These eggs (dwarf eggs) may tend to infertility, with little yolk or very pale yellow yolk being visible. If, however, the egg is fertile there is a possibility (only a possibility, as chick weight at hatch does not necessarily correlate with later body weights) that selection for these eggs could assist in the selection of smaller birds (However, this goes against the "Standard"). Body weights in some species do not correlate well with egg size, and birds that are predisposed genetically to be large, can under the right conditions, attain their genetic target even if they appear small or delayed in earlier stages.
The one sure thing about breeding is that one never really knows with 100% accuracy what is going to happen, given a large enough sample. Breeders try to reduce the odds of something undesirable occurring, but it can lurk undetected in the genome and then reveal (re-assert) itself at a most inopportune moment. Larger eggs than average may assist with selection of larger birds, although this seems a debatable issue. Eggs that are smaller or larger than the average tend towards infertility, so in essence la live chick on either end of the range may well have a greater predisposition for large or small size.
The egg shell itself is very important in the control of gases (Co2 and O2) and moisture. Shells can vary from quite hard (lots of calcium) through to thin shelled (thin wall of calcium) and finally to soft (or no) shell. The more porous / thin the shell, the greater the likelihood for high chick mortality due to its inability to regulate moisture loss. As I understand shell inheritance, thickness or thinness of the shell is highly inheritable and as such, the breeder will want to be aware of such a problem and to check this possibility if a high percentage of eggs fail to hatch and are dry when examined. Some breeders attribute failure of eggs to hatch to dry or low humidity environments. This may well be the case, with breeders achieving better success when adding moisture by wetting the hen or putting moisture where it will work best. The requirement for water would seem obviated by the peachface's country of origin and the geographical climate. It is, overall, a surprising "achilles heel" for such a hardy and tenacious little creature.
Dry eggs can result from a soft shell or a crack, checked or punctured egg. One expects punctures to be more prevalent among virgin hens and cocks that scramble over the eggs if startled into or out of the nest box. However, punctures may also occur among an older pair if the claws are not maintained. The Japanese Yellow (U.S.) might be a good example of a thin shelled egg (soft shell) producer. In the homozygous form the egg produced is either very thin shelled or shell less, which means the eggs are extremely fragile and susceptible to slight variation in humidity or heat /cold. There is some belief that this condition might be related to a calcium mal-absorption and synthesis issue, so that even if the bird is ingesting cuttlebone or some other source of calcium, it is not absorbed and transported to the "shell gland".. The "soft shelled" egg can result in egg binding as it gets trapped at the pelvis and the muscles that usually expel the egg may not be able to acquire a firm grip on the egg. The egg may also flex and bend to accommodate the contractions and eventually lead to spasms. I have not heard of Japanese yellows having a greater propensity for egg binding than normal birds. Would someone care to comment ? Cracked eggs are an obvious way for the fragile environment inside the egg to be subject to rapid changes. Checking is another way for the egg to become more susceptible to external fluctuations, as this may combine with the porosity of the shell to potentially increase moisture loss or prevent CO2 levels from reaching high enough levels to activate the hatching reflex.
The presence of a soft shelled egg (form maintained by albumen layer) is a sign that the yolk may not have entered the oviduct or infundibulum (funnel part of the reproductive system) and has instead dropped into the body cavity. If yolks begin to accumulate inside the body cavity, they will infect the surrounding area and can lead to peritonitis. The hen may not fly much and may eventually huddle on the floor, her movements will be awkward if she attempts to walk away from you. If you notice soft shelled eggs, and you open them to find no yolks, it may be worthwhile having her checked. Soft shelled eggs should result in a check up at any rate.
Egg binding can also occur when a hen fails to produce a proper (full) shell layer around the albumen. In this situation the unshelled component of the egg can adhere to the lining of the uterus and remain there until the breeder notes a problem with the bird and takes her to the vet for treatment. An older hen may have problems with producing enough shell to cover her egg and consequently, her probability of egg binding increases (there may not be much warning in this situation unless her egg to nestling rate has decreased precipitously). Virgin hens (under 10 -12 months) are supposed to have a higher risk factor for egg binding complications. I haven't seen any rational for this, but perhaps it is because: 1) there are substantive, competing demands for calcium when the hen is growing quickly and either approaching her first molt or has only recently exited it and 2) The reproductive system is slow to develop; egg laying supersedes mature growth attainment or some of the muscles areas required to expel an egg are not fully developed or tire quickly (Many people will not consider breeding their birds until they are at least 12 months. Males are usually active earlier). Egg binding in older birds may be more of a question of the hen's productive egg laying years and the withdrawal of calcium from the bones where calcium is available in limited quantities and cannot be assimilated readily, while egg production continues unabated.
Fertility or lack there-of is always an interesting topic. Both the failure of or development of an embryo can reveal a tremendous amount of information about fertility; lethal genes; malformation and mutations and other hereditary characteristics. Much of the work done to-date has focused on chickens because of their economic importance (eggs and meat). However, dedicated individuals have also been working on parrots and their behavioral; reproductive and hereditary traits (although linked more to color mutants and behavior, "on the web", than anything else). A tremendous amount of work has been undertaken in the area of artificial incubation in the larger, more valuable, psittacine species that might be attributable to the smaller parrots.
The lovebird, despite its numbers, appears to be like the canary and the budgie, where people watch for general health and breeding results more than fertility issues. This is not to say it is ignored, just that it does not appear to have been a significant issue for lovebirds. Canary breeders and Budgerigar breeders will have been more aware of fertility issues with the different varieties and the advent of the buff budgie, and the down and feather density around the vent.
Many people tend point to inbreeding as the causal factor in a steady decline of fertility, impotence or lack of interest from the male or female. This may not be altogether wrong, but it certainly does not seem overly correct either. Inbreeding is used as a tool to improve specific characteristics or traits and we can see from historical data on the chicken that substantive changes in any single factor trait can be accomplished in a 4 to 5 year period through aggressive selection. Like any other species there appears to be a range of fertility ranging from prodigious egg producers to those that lay few if any eggs ( 7-9 to 2-3). Depending on your stock and the number of lines that you have, if you are not watching for fertility in related lines, your chances for developing less fertile stock may increase as you move forward. This is more likely to occur when a single factor improvement is being sought over all others and other traits are left, in general, to chance. If a line of birds reveals problems early in the selection process, the breeder should make a decision to cull the entire line and related birds or immediately begin to improve fertility through selection of the most fertile in the line and stock. In some cases the breeder cannot make the decision to destroy a show bird of of low potency or interest. As a pet owner, one would swoon over the bird and be delighted with its company. The breeder, usually dependent on the birds and their showing for cash flow is faced with some very difficult decisions, while trying to determine what can be salvaged. Why ? the breeder is looking at the culmination of years of work balanced in the hand. If all those in the line are similarly impacted by the problems of the cock, can fertility and vigor be improved by crossing out ( an option if the breeder has recognized and accepted and consequently selected for fewer birds per nest in pursuit of the winning bird). If an outcross is made once and the F1 are immediately bred back into the select line (homozygous for many of the desired traits), how long can the "cold blood" last before the breeder faces the same situation and how many problem genes has the breeder introduced back into the "pure bred " line.
There does not seem to be any reason why infertility should occur through careful inbreeding, other than through an aberration of a chromosome or the accumulation of genes or modifier genes in a particular animal or line that prevent or interferes with fertility or egg production. Selection of good breeders, layers and hens should see your nest full of young.
Infertility has recently raised a spectre in the longfeather lovebird (longfeather a.k.a. standard type roseicollis). This bird has raised many questions as to its origin, but the response appears to be that the bird is the result of an intense selection process which resulted in a larger, more brightly colored bird with broad head, chest and legs. The longfeather also has earlier color presentation on the skull and mask and is thought to have buff feathers and higher down density. Given these changes in the peachfaced, it seemed a wise course to examine the effect of feathering in canaries and budgies. I am not sure about pigeons, but certainly buff feathering appears to have generated equal levels of concern and excitement in the budgie world, while the canary breeders have been dealing with "feather" types for so long that nothing seems to surprise them much. One of the challenges associated with the appearance of "buff" and "down" in the budgie was that some breeders experienced an apparent reduction in fertility, while others were not experiencing any problems. Some breeders are trimming feathers around the vent to enable better contact between the cock and hen during the treading activity. Others are beginning to utilize the "some-what" controversial, artificial insemination (A.I.) technique. Curiously enough the "buff" feather attributed to the longfeather peachface does not sound to be as problematic as the broader / thicker pubic bones of the hen, which may cause egg binding. I am not sure if anyone is trimming the vent feathers of their longfeather in an effort to improve treading success or whether it is even an issue. Comments from Longfeather breeders ? Anyone trying A.I. ?
More common infertility issues are derived from inadequate nutrition; inexperience; mutations that kill an embryo before it can become a blastoderm; incompatibility between birds; stress and change in surroundings; physical problems with the reproductive organs; disease; temperature; some say loose perches (they do reproduce in trees, and hold onto the hens feathers!); infection in the egg before it can develop; interrupted treading; secondary infection or genetic interference, and inability to absorb required minerals or nutrients.
Eggs and Temperature Impact
This is an interesting area of the theoretical and anecdotal, where the temperature gradient is often viewed as a critical element in the hatching of young birds. One fact that is indisputable is that excessive heat or excessive cold will kill developing embryos. There are the cases of hardy youngsters that survive to hatch during significant temperature fluctuations, while many if not all of the other chicks in the nest fail to exit the egg. Excessive heat in a high nesting place that is not ventilated, and is not cooled by the hen's exit from the box will undoubtedly result in no hatching. Conversely, lower temperatures, may delay the hatch date of the chicks by several days, but they may survive.
There are stories/ myths ? that heat may preferentially (in chickens) kill hens in the egg. Does anyone know of anything similar in lovebirds (experience or documented cases / information) ?
Clutch size is a factor to watch for in the breeding process as well. If you are working with the goal of increasing size and shooting for the "Standard", you may want to limit the size of your clutches. The hen will often seem to rotate her eggs around and move them to the edge of the nest depression while she sits on one or two eggs and then moves again. In some cases the hen cannot deal with the clutch size and commensurate with hatching, a young hen may forget to turn or sit on her eggs. A large clutch may not be incubated as well as need be and eggs / chicks can be lost. In some budgerigar cases it appears that a breeder with prize (show / champion) bird sitting on a normal clutch (4 - 5 eggs) remove all but one or two fertile eggs and foster them out to other "foster" pairs. The reason for doing this is fairly straightforward. The hen devotes her time to hatching and feeding one or two nestlings. The progeny benefit from the hens devotion and the extra feeding. Larger birds require greater intake in order to optimize their health and size potential and they are given every opportunity. Do you do this and what are your thoughts ?
In chickens there are the cases of eggs being impacted by temperature, but more in the incubator system. Higher temperatures resulted in more rapid growth and an early hatch. Unfortunately, the chicks do not survive very long because of the rapid growth.
Shape of The Egg (Why Oval)
The oval form of the normal is desirable because it assists with the positioning of the chick in the egg and enables the chick to rotate itself with its head in the air pocket ready for pipping, if the correct temperatures and humidity are present. The large end of the egg is elevated higher than the small end and consequently the chick has more opportunity to rotate in the correct position. I am not sure at what stage the chalazae disappear to enable the chick to turn upside down. I surmise it must be midway through the hatching period.
Hatch-ability in poultry is impacted by the ratio of yolk to egg white (1:2) and I don't see any reason why the same should not be true for lovebirds or any birds for that matter. The brighter or darker yellow the egg yolk, the greater the "hatch-ability " of the egg. The yellow is often associated with vitamin or nutrient storage and we know that the free range chicken has a much darker egg yolk than the captive chicken. In some instances the color of the yolk is caused by coloring or food intake ( pink fleshed trout with a shrimp diet and flamingos turning pink from their diets). The lighter yellow yolks appear to be indicative of vitamin A deficiency and we know that candling eggs can show a full yolk, a darker versus lighter yolk and the bare traces of a yolk. In most cases the egg with only a trace of yolk turns out to be infertile.
Damaged Egg Intervention
Birds often puncture or crack their eggs, particularly when you are dealing with an unsettled pair or pairs. Nest inspections depending on the hen and her experience can be quite enjoyable or a nightmare. The calm hen will sit quietly after you knock on the nest box and open the box to look in. She may move up to the next level and watch, she may move slightly to the side to let you look or carry out your daily routine, or she may spread her wings and cover the eggs, go for your hand or fall on her side ( not sure why !). A nervous or flighty hen will attempt to flee through and over the eggs or take a nip at you. In any case the breeder becomes familiar with his birds normal response to these necessary intrusions. If an egg looks to be punctured by an overlong claw on one of the birds, fix the puncture and deal with the birds by clipping their claws and ensuring they are smooth.
Hatching is another time when you might run into egg challenges, where the young are late hatching and you want to check the contents and candling is no longer sufficient. In this case you can open the wide end of the air cell and check. If the chick is alive, when you expected a dead-in-shell, acquire a large enough piece of shell from an earlier hatch or hatch from another nest box: you need to be fast here, as the hen usually eats the eggshell. If you cannot find a large enough piece, but you have infertile eggs in another nest box, take an infertile egg and cut a piece large enough to cover the viewport you created in the fertile egg. Disinfect the infertile egg piece before placing on fertile egg. Ensure the infertile piece barely overlaps the existing egg. This will reduce the difficulty for the chick in hatching. One seems to be able to use spackling (plaster compound) spread very thinly with a toothpick or a white craft glue used very sparingly. If there is a puncture in the egg and you catch it before it has gone to far, you can chew on some paper and stick it over the puncture or use spackle. If anyone has other repairs or tips please send them.
Malposition and Malformation
This is exactly as it sounds, at some point the embryo will shift within the egg and orient itself in the wrong position: head in the small end and feet in the large end, where the air sac is located. The malposition in this case restricts the bird from obtaining a good purchase in the egg and the head cannot move enough to pip. If pipping does occur it is unusual for the chick to hatch.
Aside from the unnatural positioning of the embryo within the egg, there is always the chance that the embryo has inherited a lethal gene (s), which kills the embryo at a certain stage of development or there is a physical malformation which prevents the embryo from hatching. This may be a beak that is malformed and unable to penetrate the egg-shell, or a deformation of the skeletal structure that prevents the embryo from applying the force necessary to penetrate the shell.
Damage to the eggshell or an overly porous shell can spell significant trouble for the embryo. In the case of damage to the egg, this more often by the parent bird, but unless it is treated rapidly the embryo will quickly dry out and die. This often occurs in the earlier stages and the embryo can be found semi- or almost completely developed, but attached to the side of the egg. In the case of excessive humidity and porous eggs, the water can build up in the egg, with the result that the chick swells in the abdominal area, back of neck and other areas that are susceptible to moisture build up. Parts of the body are overlarge as a consequence of high humidity, while other parts look extremely small and fragile. Most of these chicks will die, as water volume and the chick's size make it difficult for it to engage in an effective pipping process. pip marks can head downward towards the narrow end of the egg, so if humidity is high, you may want to watch your egg situation carefully.
Incubation of the Peachfaced Egg
Does anyone have information vis a vis development (stages /pictures) of the peachfaced egg/embryo, daily weight changes at certain temperatures and humidity or hatch-ability from various incubators that can be included here.
Which incubator is the best for incubating lovebirds in, in your opinion ?
Like many avian species, the issue of incubating eggs and the necessity for it usually arises at some point. Why incubate parrot eggs ? Incubation might be initiated to save a rare species or to replace a hen that was killed or died during an incubation period. In some instances incubation may be undertaken to build up stock birds of a certain species for trade or exchange.
Lovebirds, overall, seem to be very dedicated parents, looking after the eggs, brooding and hatching them with little trouble and more often than not they will spend a lot of time feeding the chicks well after they are out of the nest, sometimes letting them return to the nest every night, until the hen recycles and a new set of eggs is laid ( some hens can be very nasty when they go back to nest, others seem indifferent to the young, with the male doing most of the chasing or attempted chasing off of the young). Despite the majority of lovebirds with good chick rearing skills, there are always a few who are poor parents and who fail to look after their offspring. Some may go as far as to eat the eggs or kill their own young. Incidents such as these would need to occur on a frequent enough basis for concern to arise, but even if it did, why would you want to raise the offspring as there may be a chance that the trait is hereditary ?
A breeder would not be interested in birds that could not improve the line or strain being developed. Quite obviously, parents that plucked, ate their young or destroyed their eggs would not be suitable as foster parents. The incubator is a back up to assist you with your birds when and where the need arises. The prolific nature of the peachfaced would suggest that an incubator is not necessary, but in years past, several of the "rares" were reported as being quite prolific, but that prolific nature seems to have dropped off as much as the size has. Why ? Do we know ?
The incubator is also a useful device if you trying to determine why you are running into a number of infertile or dead-in-shell chicks. The incubator can assist you in finding out if something is going wrong in development of the embryo or chick and enable the handling, candling and intervention that might be necessary to find out.
As a breeder you will get rid of these birds and not worry about it (no time), but that doesn't help identify what has happened. An incubator can help you find out if the eggs are ever fertile, whether the blastodisc ever develops or at what stage the chick (s) develop to before dying. It will help you identify obvious alterations in the physical structure of the embryo or perhaps find clues to its demise. It will help you identify how the yolk looks and numerous other pieces of the puzzle. This page is for those odd things that you might have experienced during your breeding process and for those oddities that one essentially ignores during raising large numbers of birds as it is uneconomical to speculate and time is precious.
As I understand it: