Mine have been eating Maple tree "helicopters", especially now that they've started sprouting. Much easier than trying to peck the seed out. I have piles of them under the trees - when I see them start to sprout, I toss in a double handful.
I love giving them things that would otherwise be considered waste. Or bad - like when I rake up the dried crabgrass areas. It's full of seeds, so I don't want to put it on the compost or garden, but it turns out chickens LOVE crabgrass seeds! It's a two-fer! feeds the chickens AND keeps much (I wish all) of the crabgrass out of my lawn. I even bagged up some, so I can give it to them later.