Also, when keeping rats outside, they will get heatstroke, even if they are in the shade. They should be kept in temps around high 60's to mid 70s. I have 3 rats and 2 are kept together, but if cleaned out once a week they don't have any odor. Yeah Gin, ours go to the bathroom in a specific corner too. But all in all rats are very clean animals, spending the majority of their day cleaning themselves. So you might want to reconsider keeping them inside so they keep producing healthy babies for you.