Chickens are omnivores. That means that they, just like people, will eat just about anything.
I was in the barnyard when I noticed the buff hen was going after something. She was working hard at pecking it, which caught my attention. I thought at first that it was a scrap of cloth or something like that. I got closer and saw that it was a small frog! She was playing with the frog like a cat plays with a mouse.
The frog was tossed into the air, then neat as can be, the chicken plucked the frog up with her beak and swallowed it. I guess that hen got her protein for the day.
Chickens spend most of their day scratching the ground to turn up things to eat. Chicken feet are well adapted to continually scratching up the dirt.