It depends on the animals. I have 2 males, one crests up easily, sometimes with just a change in photo period. The other won`t crest up unless he has a minimum of 2 month cooling around 42 F. If you are overly eager, you can try to warm them up a little and see what happens, you can tell rather quickly, within a week or two whether or not they will come into breeding. If they don`t, just cool them down for a few more weeks, maybe at a slightly cooler temp.