Sheldon's hind quarter cramps every now and again he will have trouble with it for a while then it will stop. I make sure he has plenty of water down because I have heard dehydration can cause cramping in the limbs but that doesn't seem to have any bearing on it....Vet doesn't seem to worried about it I just sit down and massage his hind quarters till it quits. Sometimes I wonder if he tightens his muscle up on purpose because he knows I am watching and will massage him...LOL