This is what was recommended by the member who began the big caponizing thread: "The first step to caponize is to starve the birds to reduce the size if the internal organs. 36 hours without food and 24 hours without water. For example on Thursday at 8PM I took the food away. On Friday at 8AM I took away the water and put the roosters in cages in my basement. On Saturday after 8 AM I was ready to get started." If they're being kept in a cool dark place they won't be too bothered by this, and if it helps make their operations go faster it's all for the good. I think it helps to keep them in a dark place, they just think it's an extremely long night.