I kept my rats In my attic a few year ago. My attic in the summer was getting to 90.f and in the summer I saw production almost halt with more deaths and lots of pinks not making it. I switched them into my basement and now it never even gets to 75,f I have much much better production, barely loose any, including pinks and adults. It also cut down on how many times id have to refill their water supply. In short the hotter it is the more work you have. I really like my set up i have now. Ugh that attic would start to stink in a day. Now I never smell them.
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