I know a couple of breeders whom just use an ambient temp control no not spots. The idea is to provide optimal core temp to the animals so there is no need to thermoregulate at all. there are a couple of issues with this logic the first is one of control. The single breeder I have been in a snake room who does this have very rigid temp control, he sees a 1/2 ºC (1ºF or so) variation up or down and has very accurate thermometers.

The second is a guess, what is the ideal core temp for a given snake? Babies it is lower than sub adults and adults that means three rooms not just one. The idea core temp is also a bit of a guess, some say 85 some 88. There is little to no hard evidence on the matter. I have adopted two of the 'problem feeders' from this breeder and after a year one has never refused (2300 gm female) and the other refused only a few times. I provide them a gradient why they eat for me and did not feed for him is anyones guess but mine is those individuals didn't like the temp HE decided was the best temp for them.