Monk and Chip have been living together since they were young. They play and roughhouse but today, while we were working on the rat rack, I noticed that Chip was limping. He is favoring his back right leg, holding it up and not wanting to put pressure on it. There is nothing really he could have fallen from other than the water bottle holder but I've never seen either boy try and climb it. I plan on calling the vet and seeing what she thinks.