Hi, I have a 15 week old guinea that was fine up until Sunday morning when I went out to feed them. I noticed it fell to the ground and can not walk. It can stand but stumbles over like its drunk. Its still eating and drinking and wants to go out with the rest of them but it just cant walk to go. we have put it in a separate little cage to keep it from hurting itself any worse and have left that cage in so it can be with the others. I am at a loss as to what could have happened. There are no wounds or breaks and its legs look fine. Any ideas?