Hi all, i keep many a species that require proper brumation. Over the past decades I have kept species of Chelonia warmer than their wild range ( i live in the Phoenix area) this resulted with fertility issues . In my opinion it is extremely important to get a good understanding as to the wild annual weather ranges of each species and do your best to duplicate it . Many of you have chimed in with different methods and that’s all good. It is vital from a reproductive standpoint for the animals to cycle. For years i had issues with none viable ova with Radiata , and i discussed it with Colette Adams of Gladys aPorter Zoo, and her advice was to lower the thermostats Down to 50F in the overnight boxes, and the following year the fertility was up by 40%. The point i am trying to get at is,if your goal is to reproduce/ propagate a species it is important to cycle them with with proper brumation for optimal fertility.