there 1 week old
Welcome to BYC!
How old are these chicks? If they are still quite young and in the brooder, chances are you need to give them more room and lower the heat. Being cramped and hot will make them attack each other. They can hurt each other as well. So if this is the case, more room, less heat. If they are older and are not over heating or over cramped, you may just have a bully chick. You would need to separate this one out for a while to help correct this behavior.
Good luck with your babies and welcome to our flock!