I’m sorry the chicks are dying. The most important thing is do not let them start another clutch right now. Whether the chicks survive or not, remove the nest box as soon as the chicks are no longer in it. Hopefully because some survive and leave when they are ready – about 5 weeks old. If the hen lays any eggs while she still has chicks, discard the eggs.
If this was their first clutch of eggs, it is normal for it to fail. Most first clutches fail because the parents do not sit on the eggs or do not take care of the chicks. However, you always need to remove the nest box in between clutches, and rest the pair for 6 months. You cannot allow them to have clutch after clutch or the hen will end up dying from laying eggs too often. In the wild, they only breed once a year, so they are not intended to have more than one clutch per year. You can allow two per year as long as you rest them in between.
I’m guess these are parakeets since you asked about feeding fresh foods? Are they at least 2 years old? If not, this is part of the problem. Younger birds may be able to reproduce, but they should not be allowed to. They are still developing physically and mentally, and younger birds are often more interested in the mating part, and not taking care of eggs or chicks. A young male might even eat the eggs or kill the chicks because he wants the hen to mate with him again. Some young pairs get bored with feeding the chicks and stop, so the chicks end up dying. Some young pairs just have no idea what they are doing – they may feed too much or not enough.
Your pair needs to be on a nutritionally balanced diet. If they are only eating seeds, this is the main reason the chicks are dying. Seeds offer almost no nutrition, and the chicks can’t survive if the parents only have seeds to feed them. Both the parents and the chicks need good nutrition and a lot of healthy foods. You should be feeding them NO loose seeds – they need a nutritionally balanced diet like pellets, or our foraging diets. Our foraging diets are formulated the same as pellets, but the ingredients are not ground up. We use fresh, human grade seeds with the hulls removed. They are combined with other nutritious ingredients and coated with a nutritionally balanced binder. The problem with feeding loose seeds is the seeds are usually not that fresh, and they have hulls, so if any vitamins are added, they are lost when the bird removes the hulls. Along with their pelleted or foraging foods, you should offer dark, leafy greens, chopped veggies and some fruit. They should also have a cuttlebone. Each time you give them the nest box, you need to feed them an egg food. This can be a dry commercial egg food, or you can cook and egg with the shell washed, crushed and cooked with the egg. The egg food provides protein and calcium to replace what the hen loses when she forms each egg. You offer the egg food until the chicks are weaned. The parents will feed them a combination of these foods.
You should not let your birds have a nest or incubate any eggs until they meet the criteria I described – at least 2 years old, nutritious diet and at least 6 months since they last had a clutch of eggs. If you get them on the good diet and provide everything they need, and the chicks still do not survive, then you probably should not breed the pair again. Some birds never make good breeders or parents. But they should be given at least 2 chances since they do need to learn.
Thank you for asking Lafeber,