When I set pet trades with people, sometimes I'm the one who needs the junk pet. I keep junk pets stored in my Show Room, so I know where they are when I need to trade, but it takes me a while to look and see which pet is in what category so that I can find a junk pet.
I think it would be easier to remove pets from a rancher or Show Room if we could remove them by category. So that if I was looking for a junk pet, I could choose 'Junk Pets' and all the Creatu in that category would show, then you could remove it that way. That way, if there's a pet in a certain category that you want to remove, you don't have to scan through your stocked pets. You can just choose the category, and those Creatu will show.