Yes, the hair pulling is probably just the young wether being playful/weird lol. Are they bonded? If not, can you put the old one with another goat who won't pull his hair?
Or it could be the protein thing, I've never heard of it but it seems others have..what exactly do they eat every day? When did you last have fecals run on them?

Or it could be the protein thing, I've never heard of it but it seems others have..what exactly do they eat every day? When did you last have fecals run on them?
For your old goatie, what other problems is he having? We may be able to help.