Is something wrong with my chicken?

My chicken Butters (hehe). She is a lot slower then a lot of the other chickens. She doesn't have good balance and either she is a runt or is the youngest one of them. She has an arched back and a long neck. She can roost fine but she gets scared of jumping off high roost or high areas. She can fly really good. When I say shes slow when everyone is inside the house and there might be 2 other chickens outside but in another spot she just sits there and does nothing unless I go up to her she comes back to earth. Everyone loves her and she is a really nice chicken she doesn't bother the baby chickens at all. She is pretty to. I'm just really worried that if she goes in the woods on her own instead of staying with the flock she might get eaten or hurt if she goes to far. She's my favorite out of the teens and I've already lost the first 4 chickens who were the adults and now I only have the 2 left out of the adult chickens.