Hello Alayne, Not sure about the two kinds of marshalls, but it made my ferret's poop extra stinky. I think the fish oil has something to do with it. But if they like it and you don't notice a if difference, go for it. As far as learning about other ferret food brands, check out the ferretstore.com They have a large variety and a really cool ferret foodchart analysis that tells how much protein, fat and other ingredients each brand has and compares each. Personally I like to mix a whole bunch of different kinds together, since ferts are so picky about trying new stuff. This way if any of the brands become unavailable, I still have a lot to chose from. Mixing the new kind of food in with the old is a good way to get them used to it. I have a large sealable bucket, holds 20 lbs., that I bought from the ferret store and I mix everything in it all together. I usually use, Path Valley, Sheppard and Greene, 8 in 1 Ultimate, The Ferret Store Superior Choice, Totally Ferret, and Mazuri. They seem to like it. Good luck, suzi [Posted in FML issue 4082]