why are they causing problems for your kids. They may be feral, formerly trapped and neutred, and are being fed by someone. Why do you think that this is any of your business? if they are neglected then fine - call a cat rescue or dspca.
1. Like every living creature cats eat and subsequently drop their "puddings" usually not on their own patch. Their "puddings" contain bacteria which can be harmful to humans and can cause blindness in children.
2. Anybody can feed a cat. A two year old child can do it. But, I've never seen any cat lover cleaning up faecies dropped away from the cats' home patch.
3. Somebody suggested that the OP should get a dog. Great! - if he wants a dog. But, a possible solution to the problem.
4. If the OP wanted a cat, I'm sure he'd get one. But, it appears he doesn't want a cat and should not have to endure the presence of several cats that he doesn't need or want.
5. I don't know the physical layout of the OP's garden. But, if he can put a wire fence around it he has a chance of preventing cats entering his property. That's of course workable if somebody doesn't cut holes in the fence.
6. There are chemical cat repellents that can be bought, but from what I hear are as next to useless as makes no difference. Stones on flower beds with some citrus peels are useless too.
7. There is no point in chasing cats from your garden, they will just return when they feel like it.
8. Cat owners have an obligation not to inflict their pets on those who don't share that love.
9. We have two dogs that can go from 0 to 60 in four seconds; any cat entering our property would be a brave feline; sorry! probably would be a former brave feline if it can't go from 0 to 61 in three seconds.