David, I will respectfully have to disagree with your low temp theory.I have routinely dropped room temps with my chondros into the upper 60's to low 70s with little effect on the animals. I have kept babies and adults in the same room during the process. The only animals that have had night heat are babies. The rest get their heat turned off at night year round. IMO, 89 is too high. In my observation, my animals prefer temps in the low 80s, right around 82....which is why I shoot for a hot spot of 84-85.
I'm going to call this one plain ole seasonal fasting. I have noticed most males will continue to fast even if temps are raised. Outside barometric pressure can make these animals behave in ways we wouldn't normally think of.