That is the most ridiculous thing I have ever heard....a snake wont feed in a larger enclosure. I do not have a ton of experience, but the 2 bps I owned in the past were purchased small (less than 12inches) and went directly into a 4 foot long tank and I never had feeding issues with either one of them.
Those poor snakes.....that looks like animal abuse to me. I'm all for simple enclosures, but they should be an appropriate size!