is it possible that he has metabolic bone disease? this would be caused by a lack of calcium and possibly other nutrients. is there anything in his enclosure that he could have injured himself on? they don't normally break bones unless they are weakened by mbd or something traumatic happens.

you really shouldn't wait until after july 4th--by then the bone will already be healing in the position that it is in now and any underlying causes may have had time to further develop. are there any other vets you can try?