Id say it's just her being tired of getting mauled by kittens all the time. lol
Imagine Moms with their kids lol
My neighbor's cat came home with a kitten last month. No idea where he got if from. We went house to house asking if anyone had a cat with kittens, but no one did. He brought it home to show everyone, cleaned the kitten and gave up his bed for it. Cats can do odd things.
That's normal. She's not going to hurt them. It's just really hard being a mama cat. :-)
So like I can't let them take u away