Today, my main group of chickens got a 5 pound organic cabbage that ended up with some cabbage worms eating the outer leaves.
We had plenty of cabbage plants without any worms, so I pulled the wormy cabbage and gave it to them.
They ate most of that head of cabbage in one single day. Worms and all.
During harvest season, I often give them homegrown organic tomatoes as a treat. I give them fruits that have problems -- either they are grossly deformed, or they have the beginning of blemishes developing, or they have some kind of other problem. I may even cut off the bad parts of the tomatoes and then give them the good parts.
I occasionally give my chickens a watermelon treat.