Lexie is 14 weeks old... she bites sometimes but its not like an "i wanna kill you bite" shes a puppy.. and they might be big but their pups too. They might just be scared.. or it could of just been a nip.. like what lexie does.. not really a bite that means anything. Im sure if they have some classes or good training and get to know you and are associated with other people they will make awesome pets. Theres no reason to put a puppy down.