I used to have litters that would shed out into patchy looking weirdness. That was back when I used to keep them in a 40 gallon cube tank until they got enough size on them to put them into troughs to grow the rest of the way to adulthood. I installed a fan to move air around more. Once they started getting more airflow, they stopped being patchy.
Not sure if it will work for anyone else, but it seemed to work for me and is a simple "worth a try" kinda thing.