This. I've noticed that my older adults (> 4 years) slow down a bit over the winter. I don't bromate them but they still are aware of the seasonal changes. They more than make up for their mini-fasts in the spring though.
Bear in mind that most colubrids in captivity are overfed, which can lead to an early death due to obesity issues like fatty liver disease. Kings, corn/rat snakes, milk snakes, etc. should retain a more square than round body shape.