Teddy refuses to eat

[Cathy1]

I adopted Teddy around Jan. 23. He is around 14 yrs old. We were feeding him Royal Canin, but decided he didn't want that anymore. We have tried Science Diet, Wellness, Natural Choice, Iams, Pedigree, and even Ol'Roy but won't eat any of it. We started giving him our food and that was okay for about 3 days and now doesn't want it. But he will eat feces, his own or our other dogs. I am now cleaning up regularly and watching closely. We have spent $1100. on vet bills since we had him and they cannot determine what is wrong. The vet tech even took him home for 3 days and wouldn't eat for her either. We have been to 2 vets and neither one can find a problem with Teddy. He was 43 lbs 2 weeks ago and now weighs 36 lbs. Any suggestions? He will not eat hard food either, we have 3 bags here that he won't touch.