I think your chances of getting the kids help by calling child services on a cop are remote. I think there is a much better chance that the kids will pay for that call at the hands of their parents.

I keep doing what you're doing (minus the stress), keep treating the kids the way you would want your child treated if somehow you weren't able to take care of him. It sounds like you're doing a great job already - but as a bonus you are awarding yourself massive amounts of stress. Stress is optional.

I find for myself that once I make a decision, stress goes down. It seems like everything you're doing is a guess to you, i.e. "Should I be bandaging him up or should I go wake his mom. I guess I'll bandage him up." If you realize and accept the evidence that they're unskilled and perhaps uncaring parents then you are left deciding whether or not to call child services.

If you agree with me that child servies is a bad idea and will cause even more trouble for the children, then operate from those two conclusions. Bad parents, system fails. Now what do you do? The best you can for the kids. They aren't your responsibility but it sounds like you are willing to do some things for them. Great. Do what you're comfortable with and don't feel guilty over the stuff you aren't comfortable with.

Another thought is this: Talk to the other parents in the neighborhood and enlist them to help you feed and entertain these children. This will do two things. First it will let the children know that there are other people in the world who care about them and second, it will raise many peoples attention to the fact that these children are neglected and while 'you against a cop' in front of child servies may not work, a neighborhood against a cop certainly will.