Your new mice look lovely. What's a sepia mouse? - I don't think I've heard of them, do you have a photo of those too?
Lava ledges and other brands of perches made from pumice are excellent, and concrete bird perches while unsuitable for birds are relatively good as well (and cheap). This is especially true if you take care when placing them to put them somewhere which is much-used as a route throughout the day. The perches with a sand coating are less good for rodent feet in my experience. I use environmental things like this for keeping nails trim in exotic mice species, dwarf hamsters, and gerbils.Lilly said:I was hoping that putting things like the bird perches that help with like budgie nails or the lava rock ledges you can get for chins might help but not sure if that would hurt their sensitive feed/skin.