I love manx rats, haha. That's the first time I've seen a manx mouse, though. I have a manx girl who has had a few litters without any issues, she's just a decently put together manx, I guess. It's too bad your mice had issues, it seems as though the manx deformity produces itself a little differently in mice? From my understanding, it's not often they pop up in rat litters, even with either visual or 'carriers' as the parents. You had a lot of weird tail stuff going on with your mice, though.. hm
I really couldn't find much on the issue. It does seem that they are prone to deformity, but I have not compared the issues between the two.