Only a small percentage of the "Canaries" stay yellow. My animals turned at around 4'. Some have been lucky and still have nice bright yellow adults, but they are rare. My adults would also shift from green to a dusty yellowish-green from day to day, back and forth. I wish I still had them.
As for feeding, I've never had an adult chondro refuse frozen thawed rodents once they were established in their habitat. I've had fresh imports come in and feed on frozen thawed from the first feeding. A lot of it has to do with presentation. If you present it to them in a way that is "natural", it will usually trigger hunting mode.....especially important when getting hatchlings to feed consistently.