Not every dog does ok with black hawk - pretty sure some dogs are allergic to some of the stuff that goes in like maybe "emu oil" or whatever.
Mine does ok and she likes it. Nutritionally it could be the same as supercoat I suppose but I don't want to support a Nestles brand if I can avoid it.
Anyone who suggests I should feed Hills Science diet - I make them read the ingredients to me and starting with the first one - explain why that is good for my dog (it isn't). I had a vet nurse try to tell me that hills science chicken and rice was better than chicken and rice I cooked up myself... so I made her read the ingredients - she never had before and she was a bit surprised. I didn't buy the stuff.