Personally, that's not who I'd buy from...snakes survive in the wild with a lot less food, and I can't say for sure if it stunts their growth permanently, but I will say
that their immune system might not be as good as it otherwise might be (with more food) & maybe their bones aren't as strong either? I know it's done, but I've
bred some snakes in the past & never considered for a second withholding food. I'm a snake-lover first, never commercial, & I'd support others who do likewise.