Why cant you put the boy hamster back with mom when she alredy had babies?

It is not advised to put a boy hamster back with his mother after she has had babies. There are a few reasons for this:

1. Safety: The boy hamster may be aggressive towards his mother and siblings. He may try to fight them or even kill them. This is because hamsters are territorial animals and they will fight to protect their territory.

2. Breeding: If the boy hamster is not neutered, he may mate with his mother again and she will have another litter of babies. This can put a strain on her health and resources.

3. Inbreeding: If the boy hamster mates with his mother or sisters, the offspring will be inbred. This can lead to a variety of health problems, including birth defects, mental retardation, and immune system deficiencies.

For these reasons, it is best to keep the boy hamster separate from his mother and siblings. If you want to keep a male hamster, you should get a separate cage for him.