Great input Phil!! I love hearing what you have to say. Here is my take on a few things that I would disagree in good consience though. By the way...can I have that pinesnake pictured in your last post? HA HA! 
I happen to think that power feeding does not occur in nature because existing in nature and being in captivity are two totally different things. I believe that a snake in nature would eat as much as possible when it could because Lord knows when his next meal would occur. " Power Feeding " to myself and many others is the act of not being patient with an animal's growth rate and trying to get it to breeding size in the shortest time possible so they can produce babies in the shortest time possible. No matter what we do as keepers, we will never have the conditions to mimic nature 100% in our collections. They are completely confined to a cage, while being in nature, the animal has complete freedom to roam, travel, and thermoregulate.
Pits do have an incredibly high metabolism, and that is something I have learned in my keeping of pits. I have found out that in some of my snakes, I should have fed a little more often, or actually, more appropriately sized items. Others I have seen grow or gain weight at fast rates, and had to back off to prevent obesity. The key, to me, is balance.
As far as rats vs. mice with younger pits, I have had much better luck with mice!! Ha Ha!! I know..I was startled with the results as well. I actually now feed all my pits a mixture of rats and mice. The times I have fed ALL rats to my growing pits, I didn't see jack squat in growth rate. The mice I then received in orders and fed seemed to be better suited in size for good meals, as the rat sizes would either be on the extreme in either too big or too small, when I would get my orders in. So with mice, I have seen my growing pits reach between 3 and 4 feet in the first year. Also, I have purchased adult pits that were 5 foot and then with retired breeder mice as meals, I have seen them grow well over a foot to a foot and a half more, making them well over 6, I think. Now, is this me saying that rats suck for meals for pits. No way!! I advocate both rats and mice!! My point is finding the perfect size for your pits in terms of good meals may contribute to better growth as well. With mice, I was able to do just that, and then, in turn with giving what I was calling good sized prey once every 5-7 days, I have seen optimum growth. I do try to have pits reach adulthood in 3 years but sometimes, I have seen it take 4. Deppei and Jani I have seen grow slower, but bulls and pines seem to grow really fast. Since most of my growing pits were purchased within the last 4 years, I am still seeing my hypothesis at work and I am still learning as well, as you can never stop learning. Then, in the end, all of my biggest pits end up on small rats or retired breeder mice anyways.
Later Phil!!!

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Genesis 1:1