Apparently Deer Fern Farms since they breed their own, and they seem to be very honest people and have a clean environment for the animals. I read their
care sheet and they themselves have tried many types of items for substrates, and lights and state which one works best for them and will work best for anyone. So i would trust them. Also ive read on this website about people buying uros from them and that they havent had any problem when they got to their place.
-Lizzy