Thank you for weighing in with your suggestions. I think your plan is great if I was actually having to live with these kids in the neighborhood for any length of time. Absolutely everything you have said, and others, about going to their house and talking to the parents and kids is spot on. I could, and would do that under most circumstances.
However, these kids and their parents will be gone in a few days to a week at most, and not be back until next year. So I don't want to make a big issue out of it as no harm has been done. I'll get some padlocks and lock up the coop and chicken run. If the kids come back in the next day or two, I'll have a nice talk with them about many of the things you guys have mentioned. I think the kids will understand and it will not be a big deal.
As far as treats, I really don't mind what they offer to the birds as long as it's not something I know is bad for them. I have been good to watch what is thrown into the run and offered to the chickens. If I thought something was bad for them, I'd just go in there and pick it up for the compost bin. Likewise, if the chickens don't eat the treats the kids bring over, I'll just rake it up later and dump it in the compost bin. They only come with a small bowl of food, not buckets. So I am not too concerned.
For me, it's just fun to see the kids get such enjoyment offering food to the chickens and I am always sure to thank them for coming over and giving something to my birds. I know they go back to their lives in the city and probably never see any wild animals or livestock for another year. It's also important to me that the kids feel appreciated when they try to do something nice for others, in this case, my chickens.
So yes, I agree with all your comments and suggestions, but I'm not going to be setting up any plans for visits or laying down rules for the kids when I know they will all be gone sometime this weekend and I will not see them again until next year. Hope that makes sense to you.