Mom cat seems afraid of her kitten

Hi

Our cat gave birth to three cute kittens four months back. After about two and half months she started to actively discourage them from breast feeding. She hissed at them and started to run away from their presence. Then we gave them up for adoption. All three of them together. However one male kitten was returned to us and we decided to keep him. The problem is the mom cat seems to be so afraid of this little one. She even found a new hideout in the ceiling and started coming down only for meals. Whenever the son is nearby she would start growling and hissing. She attacks the son if he comes too near (using front paw, never has bitten though) and runs away. Sometimes growls at us even if we touch her when she senses the kitten nearby. She seems so afraid. The kitten doesn't seem afraid of mom though. He seems to think it to be normal. He tries to go near mom, eats out of her food portion and doesn't  seem to mind the attacking.

We have another adult male cat in the house and he doesn't mind the kitten. He bathes the kitten and even plays with him. This tom came to our house when he was a kitten and we took him in. The mom cat (not yet a mom then ) initially tried to chase him away but later made peace. However that resistance was nothing like what she shows her own son. It was a resistance with authority, and she never showed any fear towards him.

The other two kittens too were brought back to our house about twice when the owners traveled (only briefly) and it was the same response from mom. She refused to come down even for meals.

I have not heard about such behaviour before and would like some input.

Thanks 

First have they all been spayed/neutered?

How long was this make kitten out of your house before being returned?

By your description of events, I am guessing no reintroduction steps were done when bringing the kitten back into the home?

Having been out of the home, the kitten(s) no longer smells like your house or like he did when he was with mom. So, to her, he is not recognizable and thus, an intruder.

I suggest isolating the kitten in his own area and follow the following steps to reintroduce the kitten to your girl.

http://www.thecatsite.com/a/introducing-cats-to-cats

It's important not to rush and go at the pace your girl dictates.

Also, if you pet sit the other kittens again, best to either confine them to their own room or confine your girl while they are in the house. No need to stress her out with newbies that aren't going to stay long-term.

Thank you. I'm afraid they are not neutered yet. The little one spent about three weeks in the other house. Sure I will try to reintroduce them properly. 

Just out of curiosity, is it usual for mom cats to be afraid of or hostile towards her kittens as they grow up? Sure it could be due to the altered smell and not being able to recognize her kitten. But this started before they were given for adoption and as I mentioned earlier her response to a different kitten who was not her own was quite different.

Thank you again

If mom is not spayed, this is likely the cause of all of your issues. They often go back into heat a few weeks after giving birth and could absolutely be the cause of her hostility.

Best to get them all spayed/neutered ASAP. Kittens become fertile as early as 16 weeks of age and they will mate with each other. Once a female is in heat, she cycles in and out continuously (typically 10 days on, 10 days off), but others stay in a continuous heat.