Why have i been told to just give my rescue dog food that is only 17% protien?

asked: Ihave been doing this for some weeks but i think my dog maybe needs more..he seems happy and healthy but looks very slim and i feel he is missing that bit extra something..he has the normal doggie treats but is this enough??
he is 11years old and a german sheperd

How do you find out if you puppy is pure bred if it’s a rescue?

Beth F asked: We have a rescue German Sheperd puppy, and think it might be pure bred, we don’t have any information about his parents, how would we find out?