Chickens eat everything! Mine ate broke plates. It is amazing that they make it in the wild sometimes.
I try to make sure there is nothing bad out in the yard. I can't imagine what they ate last year when the outside of the house was painted!
Well I am learning that now! LOL Our pasture is fairly clean, we did turn over 2 large piles of fill dirt a few months ago so perhaps they found it in there. I am glad it had no negative effects on the bird. I can't imagine that eating glass would be comfortable to digest