Sounds like child services should be involved too! What a horror :( There is always the option of getting a friend to anonymously assist you but im glad you found it in you to report them. Stay on top of the authorities for sure. Document everything
You don't ever want to take someones animal, no matter how you feel, and either give it to the pound or to a vet to euthanize. You have to sign over the animal, or give permission to euthanize as owner or agent, and if the owner ever found out you are the one who signed that you were the owner or legal consent to sign over, she could come after you for stealing her animals.
She could charge you with interference if you continue to feed any of her animals and that's a whole can of worms you don't need. That is why there is a humane society. It's for them to deal with, not you.