By Ed Davis
(Reprinted with permission)
Why did this egg not hatch?· What did I do wrong?... There are several common categories of problems that you might experience during incubation.
*Problem #1: CLEAR EGGS
If the eggs show no sign of developing it is probably infertile. On the other hand it might have been fertile but it could have gotten badly chilled in the first few days of incubation. How does this happen? The hen may have tried to sit a couple of days then got off the nest when you found the eggs. It is hard to recognize any development until the third or fourth day of incubation.
*Problem #2: EARLY DEATH
When candling after a few days, a thin blood ring is recognizable in an otherwise clear egg. This is caused by the incubation temperature being too high or the egg being chilled. A stored egg that has been left too long can also cause early death.
*Problem #3: LATE DEATH
Late death occurs when he egg dies after about 40% of incubation. The two most likely causes for this are probably wrong temperature and possibly incorrect turning. Another reason could be infective bacteria. This can cause death at any time of incubation... It can cause death several days after incubation! The only way to confirm this is to have the chick or egg sent for post mortem examination. This can also be caused by heavy inbreeding. Also, some characteristics in poultry such as tufts in Araucana chickens and the short leg gene in Japanese bantams are connected to lethal genes. When both parents carry these characteristics (short leg is bred for short leg, for example), approximately 25% of the fertile eggs will result in late deaths in the shell.
Problem #4: DEAD IN SHELL
This is the most common problem among incubation complications. Death in the shell results when a chick starts to breathe but dies before it can escape from the egg. The chick doesn't have to pip the shell to start breathing, it will begin to breathe air in the air sac. Death in the shell can be caused by several things such as wrong temperature, wrong humidity, wrong turning, and of course infectious disease.
Start to look for your problem by the process of elimination. Most of us can't afford to send each egg for post mortem. Let's look at the other possibilities. If you pretty well keep a check on the temperature then you know it is not the cause. Remember even if you had a temperature spike that it may have not killed the developing chick. It takes more than a few minutes at a higher temperature than normal before the developing chick is killed. If you had other eggs in the incubator that hatched with the egg that didn't, this can probably be ruled out. You may need to look at turning but if it was turned just like the other eggs then possibly turning can be ruled out also. If you candle the eggs regularly, you will know if turning is the problem by the amount of vein growth. By the time 60% of incubation is complete you should have vein growth covering the whole inside of the egg if the egg has approximately the same air.
Just because some eggs were set at a certain humidity and hatched does not mean that all eggs take the same humidity. Some of the eggs have a denser or thinner shell; you can't tell this by just picking up the egg. They may have even come from the same hen but they still might require different humidity levels. If you have a certain breed that you are having trouble with, this may be the problem. Candle the eggs from this hen and compare them to the eggs you are hatching with the same amount of incubation. The airspace should be about the same amount. This will give you a good indication if the humidity is all right. Depending on how important this is to you, you can invest in a pair of scales to weigh the eggs to see if you have the right amount of weight loss. The correct amount is 15% loss when the chick internally pips the airspace. If you go to this trouble, you should also know that it is hard to correct the weight loss after the first two weeks of incubation. There are only two potential possibilities left. One is infectious disease. The other is possibly the parent birds. If the egg has come from badly fed parents or closely related parents than the egg could be considered sub standard, so That although the embryo develops during incubation it is too weak to hatch. If you are worried about the parents being related, maybe you should find another breeder to trade stock with. This is especially true if the birds in question are being fed the same and housed the same as the birds producing other eggs that are hatching.
If the chick has difficulty pushing out of the egg shell after it has chipped all the way around the egg and the chick is sticky feeling, The most common problem is simply the hatcher is not humid enough. It is difficult for the chick to rotate in the shell because it is drying out this is what causes it to be sticky. If the humidity is too low during the whole incubation period, then this will cause this problem at hatching also.
After hatching, if the chick seems swollen and too big for the shell, then the humidity was too high during the whole incubation period. The chick did not lose enough weight during incubation. Even if the humidity was too high during incubation, it will still need maximum humidity for hatching.
If the chick hatches very early then it might just be too high temperature during incubation. Check your thermometer. Hatching too late is probably a sign of the temperature being too low or the eggs getting chilled during incubation.
The most critical time of incubation is the first ten days of incubation Some of the breeders will set eggs under a broody hen for this time period. If you can get the egg through this time, then you can even make a few small mistakes and the egg will still hatch. But you need to remember that the broody hen cannot control humidity, she also does not know if the egg has a thin or a thick shell. She may also be too heavy for some of the more delicate eggs such as the peacock pheasants. Some time you can overcome this by placing several eggs under her to help support her weight.
Some of these solutions you may think are impossible if you only have one incubator, but there are some simple experiments that you can try. If you think your eggs are losing too much weight during incubation, then you can wrap most of the eggs in tin foil or paint most of the shell with fingernail polish to reduce the weight loss. If the egg is not losing enough weight, then you can scuff the surface of the cuticle with a fine grit sandpaper so the eggs can lose weight more efficiently. Do not be afraid to experiment within reason, after all, if the eggs are not hatching, then something is definitely wrong and needs correcting. Maybe with these suggestions you will haves batter hatching season.
Harvey, Rob. Practical Incubation
This article originally appeared in the February 1999 Issue of The UPA Newsletter. Reproduction elsewhere in any form without prior consent from the UPA is strictly prohibited. © 1999 The United Peafowl Association. All rights reserved.