My chickens live at a community garden / allotments and I encourage other people to give them stuff like weeds, bugs, veg thinnings and trimmings, produce that's not in the best condition but not actually rotten, etc. One of my neighbours there claims to be growing chickweed specifically for them when he hasn't weeded recently

Some kids came up to see them the other week and I said they could go and pick a few grapes from the polytunnel to give them as a treat, if they wanted. I think it was one of the same boys trying to give them crisps, so really my fault for not explaining at the time what they could and couldn't eat. I'll make up a sign or something when I get round to it.