it could be a touch of gastro if he of he grub and got the runs starve him for 12 hours then put him on a diet boiled fish and boiled rice little but often make sure he gets plenty of water for a couple day good luck mate
no he's eating like ahorse still and nice solid stools. just noticed it when messing about with him playing, if you try and pick his back end up of the ground he whines, or if you touch him firmly around there
am glad it not what i said if hes eating and drinking and his stools are hard it could be pulled muscle let him rest 2 or 3 days see how he goes dont let h