Using waste products in the production of animal feed is actually pretty standard practice. For example, urea is a waste product found in urine that is routinely added to cattle feed to help with ruminant digestion.
On its face it can seem very strange though, so there is that.
On the one hand, yeah animals eat poop, get over it.
On the other hand, densely packed, sickly animals with poor diets are a recipe for new diseases, and putting them in contact with products from other densely packed, sickly animals with poor diets is a recipe for increasingly novel new diseases.
Using waste products in the production of animal feed is actually pretty standard practice. For example, urea is a waste product found in urine that is routinely added to cattle feed to help with ruminant digestion.
On its face it can seem very strange though, so there is that.
On the one hand, yeah animals eat poop, get over it.
On the other hand, densely packed, sickly animals with poor diets are a recipe for new diseases, and putting them in contact with products from other densely packed, sickly animals with poor diets is a recipe for increasingly novel new diseases.