Poor chicken! It looks like its been severely debeaked or otherwise injured and lost its beak. If its acting normal and you see it getting enough to eat and drink, it should live a happy life. It probably won't be able to peck at insects and chicken feed as well, but I think it will still be able to eat. Just moniter it to make sure that it doesn't lose weight, and isn't picked on by the other chickens.
Thanks yeah I feel so bad for it. I almost cried when I first seen it. if somebody did that to that bird I swear that is so not right. it has to take long deep breaths because it doesn't have the holes in the beak