Joanne,
I don’t know which “Purina Lamb and Rice” you are feeding but the dry Purina Pro Plan Savor Shredded Lamb and Rice, Purina One Lamb and Rice, and Purina Beyond Simply 9 Lamb and Barley ALL contain CHICKEN.
Pro Plan Sensitive Stomach and Skin Lamb and Oatmeal doesn’t appear to have chicken as an ingredient, so maybe that’s the one you’re using? It does contain eggs and SOME dogs with chicken allergies MAY also react to chicken eggs, though this isn’t a given in all cases. Maybe your dog is fine with eggs.
Just figured I’d point this out, in case it helps.
