I dont know how safe it would be, but Ive noticed some of the car washes around here selling some. Its what their soaps and cleaners come in. Ive been searching for some to collect rain water, so I passed those up. Dont know if you could use them for feed or not. Also I had a friend that would get his from the school cafeterias. Food was stored in them. I know restaurants use them for storing there oil and whatnot. You might try calling some feed stores to see if they have any or know of a place you could.
Awesome! I hope it works as well for you as it does for me....
