You can tell if your dog is dehydrated by pulling up the skin on their neck. If the skin bounces right back into place, they are not dehydrated, but if the skin stays bunched up for a few seconds then they are dehydrated. If you worry that Petey is dehydrated, you can mix Pedialyte in with his water.
I hope that the runs have cleared up - but if not you might try fasting for a day and then feeding the chicken & rice.
Livin in a Newfie Drool Zone