I had a lavender stripe California King that a breeder sold me for cheap because she said that the snake was a "slow grower" and wasn't suitable as breeding stock. Absolutely BEAUTIFUL snake. The breeder also mentioned that she had even attempted to get the snake's weight up by feeding her reptilinks (a product that I am not really a fan of). I just thought to myself, "We will see..." and I didn't say anything.
Well, when I got her home and after she settled in, feeding day finally came around and I discovered the "problem" with the snake. She was afraid to eat anything with fur! She would strike and coil at any feeder that didn't have fur, upto and including very sparsely furred fuzzies. As soon as I offered a fuzzie with fur or a hopper, she would do her best to get away.
Anyway, I ended up ordering some hairless mice for her, and after that she ate like a pig! She never got over 3'10" but was well on her way to breeding weight. I had planned to breed her this year, but she unfortunately escaped her tank one night by working a hole in the screen
She is the only snake I have ever had escape, and I still think about her every day 5 months later. I keep hoping that I will find her, even though I am pretty sure she managed to get out through the doggy door
My post probably isn't what you were looking for, but when Imhear someone say "slow grown" she is what comes to mind. I can't help but think that maybe a lot of these "slow" snakes are just problem feeders that whoever has them just hasn't figured out a way around the problem.
Good Luck!
~Beau