Why is my female bird biting her cage after laying an unexpected egg?

If the eggs are infertile, allow her to sit on them until she loses interest. This could take 3-4 weeks. Taking them out any sooner may cause her to lay more. Most birds are naturally protective of their nests and eggs. Limit her exposure to sunlight. Use a cage cover if necessary. You can make the room her cage is in a few degrees cooler if possible also. Do not rub her beak, back or around her tail for a few weeks. This can mimic mating behavior. When she bites, stop interaction immediately and wait until she settles down. Prise and reward good behavior.

Laying so many clutches of eggs and raising that many chicks can be taxing on a bird. Ideally, a breeding hen should have no more than two clutches per calendar year. Remove the remaining chicks from the cage if they are eating on their own. Remove the nesting box as well. Separate the male and female. Drop room temperature by a few degrees and gradually limit her amount of daylight she is getting. This may get her out of "breeding mode" and stop her egg laying. She should be seen by an experienced avian veterinarian to make sure the inflammation around her vent is not infection.

It may be that the egg was actually pushed out of the box as it is not viable. If they will not let you in the box (where there may be other eggs), or the egg is not viable, you can simply remove it. Otherwise, waiting until night when both birds are calmer and quiet may give you a chance to place the egg into the nest.

It sounds like your bird may not be comfortable yet with being handled around the cage. Stress and feeling unsafe can cause a bird to lash out, and it may be that they feel you are intruding on their space or are going to harm them when you get close. Taking some time to bond while your bird is in its cage may help. If he or she has a favorite treat, begin by offering it every time you approach the cage, and only at these times. This will help your bird start to associate your arrival with good things, rather than scary. Once used to you just tossing in a treat every time you come by, you can then move on to opening the cage and offering the treat from your hand, petting your bird, etc. If they become too scared, try to bite, or seem very stressed out, move back to the previous step that worked and try again from there. Making sure the cage itself is kept in a stress-free and quiet environment where other pets, people, etc can't bother it can also help reduce stress and make the space more comfortable and relaxing. Bonding does take time, and it may take days, weeks or even months on each step to build that trust! Be patient, and try not to be discouraged if you don't see immediate changes.

You can remove it or leave it in there for a few days. Some birds may be broody at first and she may not want you to take the egg. It won’t hurt her to lay in it for a couple days. All female birds will lay eggs even if there is not a male present. These eggs are not fertilized so throwing them away is fine. I hope this is helpful and please feel free to post any additional questions.

It sounds like Lily may be a bit bored or wants to get out and explore. Adding some enrichment to her cage, such as puzzle toys she can chew on for a treat or something she can snuggle and preen may help redirect the behavior to safer items and give her some more enrichment. If you're able, letting her have some time out of her cage such as on a cage-top play pen, or in a safe room interacting with you can help give her some extra enrichment as well.

If the aviary is too small to handle multiple breeding pairs it may be that they are competing for nesting space, even if there are multiple nests. One nest may be seen as "ideal" and thus everyone is fighting over it. Usually, birds are separated into individual breeding groups per cage to avoid competition and ruining of eggs, as well as reduce overall stress for the breeding pair.