"You get what you pay for" and "you are what you eat"....If you want to feed the earthworms with the best nutritional value I highly suggest Earthwormorganics.net. I (and many other ray keepers) have searched everything out there and the organic grain-fed worms from Ira are the best available. I wouldn't feed Walmart or other commercially raised worms to my rays even if they were free (unless they could guarantee what the worms were raised on (nutritional value to the rays), and that they had never been exposed to harmful chemicals or parasites).