Is there any way to encourage a boy to drop the jewels?

[minimule]

I sold a colt last year. He is a very nice boy and for this area definitely stallion material. He had both jewels when he was born and hung on to them for most of the summer. He moved away to a farm that is strictly a bachelor farm. NO girls around. They do have a full size stallion but so far Mouse hasn't decided he's one yet. They brought him back home for a while to see if being around all the girls here might encourage him to "become a man"

I don't feel it is an issue of being a crypt. None of the stallions other foals have had this problem. They all kept everything down and were very proud of being a boy.