Thanks for the quick responses everyone! We are both very interested in everyone's opinions.

Tosha_Mc: That is a neat way to think about it. I would think that would be a good way to think about it, except for one thing. Being an animal science major, I have learned in several classes that the younger the animal, the lower the percentage of body fat as a general rule. I don't know how well this 'rule' translates into an animal with such a quick growth pattern as mice. I would say your assessment would be spot on for adult mice/rats in terms of fat content, but I am not sure how that would translate into a younger rat vs a full grown mouse. I would be interested for any thoughts/ numbers on that.

Adam_Wysocki: I agree that the weight of the feeders would indeed be another vital piece of information. Our record keeping was only done for the sake of making sure our snakes were growing though, and so we did not keep track of the exact weight of the feeders. I do know they were approximately the same size, and, given that her snakes grew twice as fast as mine, I know there is no way that the mice were ever half as small as the rat pups, as they would have to be to make mine the more efficient growers. I am very interested that your years of experience have shown you no apparent difference in the two types of feeders. Thanks so much for posting.

Holbeird: Yes, I had wondered about the possibility of it being the difference in frozen thawed vs. live as well. For the sample of data we gave you, mine were on frozen and hers were on live. During December, however, my roommate was feeding frozen thawed rat pups that she ordered off the internet. If you will notice their ending weights, it is still apparent that hers have maintained their stellar growth despite their food being switched to frozen thawed. We did not want to provide the data from December because we both traveled home for Christmas, and some of our snakes went off feed due to the stress of being moved. Also, we have only one gram scale, which went home with roommate, so I have no weights from the last three weeks in December.