I'm so worried! my poor little killer! for all of today he wont walk on his back left leg. He limps on the other 3. he doesn't act like its hurting him. but u can kinda tell that its bothering him. he runs fine, you can tell he kinda stays off of it but he still goes like lightening , but when he walks he just holds the little thing up

he looks sad. im guessing i need to take him into the vet, im just worried