My budgerigar has been out of its shell for 25 days, and its hair is almost ready. There is a budgerigar crawling in its nest today. It can't stand up. Was it crushed by an old bird?

It is caused by calcium deficiency. It is best to feed grasshoppers and crickets every day on the premise of getting more sunshine (not exposure). If not, drop a few drops of calcium gluconate oral liquid every day. Mix a boiled egg yolk and an eggshell (ground into powder) into a ball the size of soybeans, or three capsules a day. It will get better gradually. For timely treatment, you can also send it to a pet hospital for a doctor.