My two dogs are severly overweight and do not eat much. They don't loose their winter coats. I think they have a low producing thyroid condition. I have a horse that had an overactive thyroid(I had him tested because he was growing winter hair in 105 degree temperatures). His T-4 level was a 7 where a horse's normal score is 2.5. My horse vet said he would run the T-4 test on my dogs but is unsure what their nornal level score should be. What should a dog's normal T-4 score be?