The kosher turkey breasts I get at Trader Joes are half-breasts, usually with the keel bone. I've no idea what happens to the half without the keel, perhaps they wind up in the ground white turkey.
I haven't looked for them recently, as I consider them a winter item. I wouldn't want to run the oven in the summer, and it's only been the last few days that have been cold enough to make me think about it. I'd be extremely disappointed if they stopped carrying them.
Perhaps it would help to ask the butcher if they might be considered seasonal? It might also help to live in an area with lots of empty-nesters.