aww Im so sorry to hear about your dogs, how uncomfortable for them. I do have to agree with what the other 2 posters have said, its either probably the switch in the food or the corn. My sheltie would get some soars on his belly, they didnt seem to hurt him or did he scratch at them but they would never go away even with treatment, so I swtiched them to a grain free food and within 2 weeks they were gone.
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