I've always kept them in the cup I bought them in without incident, unless you are planning on breeding them. Earthworms are a bit easier when it comes to feeding, Dubia however will keep you in constant supply of a staple feeder once a colony is established, which in the long run will save you money. I always feel better feeding my animals with feeders that I know exactly how they are kept and what they are fed. Farm raised earthworms, well who really knows what they are being fed. I'm sure it's not fresh vegetables/fruits.