If you are breeding finches, you should be keeping a close eye on their eggs. Hens will usually begin incubating their clutch after the 3rd or 4th egg is laid. Incubation is usually shared, with the female sitting during the day and the male at night.
If you discover an egg that is not hatching, it is important to understand the cause of this problem. There are several reasons why an egg may not hatch.
Soft shells
There is a chance that as you raise chickens you may collect some odd-looking eggs. Usually this is just a ‘glitch’ but occasionally it could signal a more serious underlying problem. Soft shelled or ‘rubber’ eggs are ones which never had a hard shell formed around them, they look like water balloons with just the tough inner membrane protecting the egg white and yolk. This can be caused by not enough calcium, too much spinach, stress or a disease.
It is possible to prevent this by ensuring the hens have plenty of calcium in their diet through good quality layer feed and free-choice crushed oyster shells. It is also important to ensure the birds have adequate space and ventilation around their nests. This will help the hen to avoid excessive temperature in the last days of incubation which can cause soft shells. Excessive humidity can also cause problems.
Infertility
Before the incubation period begins, House Finch parents can spend a lot of time away from their nests. They might be gathering food for the babies, defending their eggs from predators or simply taking breaks. If they believe their chances of the babies surviving after hatching are low, they may decide to abandon their nest altogether.
An egg left out in the open could be damaged by rain or cold weather. It can also be eaten by birds or even contaminated with a toxic secretion produced from the lining of the parents’ crops.
If you think an egg is no longer viable, try testing it by dropping it in a glass of water. If it floats then the embryo is alive, but it will not be able to hatch if it hits the bottom of the glass. This happens because the eggs need to have a certain amount of water in order to break down.
Hen neglect
Hens can be very territorial about their nests and can get very upset if anyone touches or moves their eggs. They need to be left alone so they can hatch their chicks. If a human keeps poking around, talking, moving, and even touching the eggs it can affect how well they incubate them. This is the same for other bird species as well, and it’s a common reason for so many ‘abandoned’ chicks to be handed into wildlife rehabilitation facilities.
Hens may also be irritated by bullies or other hens taking over their nest. This can lead to them getting upset, and the hens will often become more protective by puffing up their feathers, making a unique growling sound and pecking any intruders who come too close to the nest.
Lastly, a hen can sometimes abandon her eggs due to having too many unfertilized ones in her clutch. This can happen if there is an infertile male present to fertilize the eggs or if the hen simply didn’t have enough time to fertilize all of her eggs before they hatched.
Overcrowding
One of the most common reasons for bird eggs not hatching is that there is too much competition. If the hen lays too many eggs and they are too close together it is more difficult for her to take care of them. She may also find it harder to incubate the eggs.
Overcrowding can also be caused by an incorrect temperature. If the egg gets too hot it can cause the embryo to dehydrate and die. It can also be caused by humidity. If the humidity is too high it prevents water evaporation from the egg. This can cause the chick to drown during pipping.
It is important to keep in mind that birds can not smell. If a bird thinks that the eggs or young it is preparing to feed are not its own, it will simply leave the nest. This is why so many so-called abandoned finch babies end up at wildlife rehab centers.
