My guinea pig Sid (who is currently displayed as my avatar) was out tonight like usual. I put him on my bed with me whilst he led on a blanket and I was stroking his tum tum which he loves and squeals delightfully aboutx). He has outbursts of shakes when he comes out almost like hes vibrating - sounds strange I know - which would not be due to the cold as he is living in a warm bedroom so I just wondered if it was me being overly worried or should I be concerned? :...