I do cool them, but not really to start breeding but to help facilitate ovulation's at the end of my breeding cycle. I drop my ambient temps 5 degrees a week or two before I introduce and once I start seeing some ovulation's and ruffly 3 months into the season have passed I'll bump the ambient temps back up 5 degrees and its like the girls line up in a row and pop pop pop. I'll have 35 to 40% of the girls that are going to go, ovulate within a two week window of each-other.