Hey I have a rat terrier dog who is 4 years old and her name is Prissy and she is currently on Purina EN dog food because some of the other ones we tried made her have diarrhea so the vet put her on Purina EN. She has started to have a rash and she is very constipated now, I dont know if it could be the food. She is getting very skinny because she will not eat the food now. But even when she will eat the food she is skinny, she will not gain weight. Any suggestions on a good food or is Purina a good food. I have had several people tell me that purina isnt a very good food.