"High protein for older ferrets (according to my vet anyways) is rough on little ferret kidneys. After I recently lost a baby to renal failure, I decided to switch the rest of my ferrets over to a lower protein diet appropriate for their age. I have always favored this product because unlike Marshall Farms, the company is not affiliated with selling ferrets for animal research. The older diet formula (Totally Ferret) is high quality with little to no mystery ingredients and gives my babies great silky coats. Also, this food keeps litter box odor down. Five Stars!"