I think there is a fear out there that if a snake eats as much as keeper will feed it, it will get obese.
I feed my snakes as much as they will eat and they still don't get fat. My exception to this are snakes that are being sold are on a maintenance diet of two small feedings per week. I only do this because of the costs associated with pinkies and fuzzies. Probably the same reason you do. It costs a lot of money to feed a large collection.
Noenates cannot be overfed because they are in a growing process. They are grwoing machines. Matter of fact, i find that faster growing neonates make for stronger adults and have a much high rate of longevity and breeding success. Most peopkle are amazed that i feed newborn florida kings large pinkies and then are fuzzy mice within a couple weeks. Then onto hoppers in less than 6 weeks. From that point bthy have huge growth spurts. It is like they are growing in front of your eyes with each large meal they take in.
My adults are fed as soon as the lumps are gone. Not after they deficate. Females have to produce follicles and lay eggs so they need to eat as much as possible. Especially since i double clucth all my females. Males tend to go off feed during the breeding season (April-july) as they are almost always with a viable female. Males get a lot of action while the females are healthy so they will produce follicles whether they are with a male or not. So they still need to eat a lot! So much for the speculation of obesity or that it can shorten the lifespan of a kingsnakes that bred to small or to young. That is what they are desined for. in areas where there is ample food the snakes will reproduce more because there is less comption and enough reserves for food in that area. Others areas migh have thin snakes because the food source is not avaliable so they shut down due to starvation.
Here is a 20" female that is 10 months old with her clucth of eggs. I had two female double clutch this year that were about as small or smaller.
Doesn't look fat does it?:

If a female is not put with a female she still goes through the process of ovulation. the only difference is the males sperm has not been introduced to fertilize the eggs. Many breeders get slugs 9unfertilized eggs) because either they don't house males with females at all times or because the female is starved enough that she does not have normal bodily functions. An example would be a woman that goes off her period if they they are on to restritive a diet. This is especially common with female competitive bodybuilders who get their bodyfat levels down to dangerous low levels for a woman. Not so with males. I guess that male snakes are much the same way and still produce sperm no matter how hungry they are LOL!
Aws far as the number of snakes in my collection, I have no idea if that is any indicator. My 6 year old daughter tried counting all the snakes in my snake room a couple months ago. She stopped at 1200 because she was tired. I still have eggs that are hatching right now so it is a constant change of numbers hatching and being shipped out.
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