Something to think about.
The situation may or may not be as bad as it seems.
While there are certainly issues from other things you have told us... Don't assume that you are getting the full story from the kids. Maybe they are provided food, just not what they want. I'm sure the parents eat, so the kids are likely provided something to eat. just maybe not a 'cooked' meal. Maybe a frozen pizza vs. ordered...
When my son was little we had child svc show up. No big deal, just had to explain a situation and they realized there was no real problem. But I had to come home from work and give a statement cause somebody was minding our business.
My son told someone (school nurse I think) that I 'threw him over the gate' Without getting details they reported it. What actually happened? He frequently got into 'situations' at night while we slept. So, we put a child doorway 'gate' on his room. One night he had climbed over it and was sleeping on the floor in the hall. I got up to get ready for work, and to avoid stepping on him I picked him up and set him in his room over the gate. Don't know if it was from when he climbed out or him kicking a little when I move him, but he got a scratch -which someone at school saw and asked him about.