Hmm, I had a mare who did that, but feeding got her moving again. Strange that you get it so often, I'd bug report it and try getting a GM to look at it if one pet is that badly affected.I still often have the problem where I tell my pet to kill something and he WON'T move.. just stands there... Oh he'll kill it but he'll wait for it to come to him and then he won't follow you until he's done killing even if you tell him to stop and follow he won't.......
Logging out closing the client and logging back in is the ONLY thing that fixes it.
Wenchy