Ken Black asks about designs for queen bee incubators. I use an incubator to hold queen cells over night. The same can be used to hatch queen bees. I obtained an old refrigerator from the local electrical store. I use an old refrigerator because it is already well insulated. I purchased a thermostat that is designed for a chicken incubator. This has less temperature variation than most other thermostats. The last thing you want is overrun on the heating cycle. I have two 60W light bulbs. Two because sometimes one blows and one will keep it going. I use rigid construction light bulbs as these last longer than normal household light bulbs. I have a thermometer inside and a digital one with a thermocouple for outside reading. I used to have a small computer fan for circulation but after this failed, and actually caused extra heating in the incubator, I never replaced it. I felt that the convection currents from the heat of the light bulbs gave enough circulation. A tray with water in the bottom helps keep the humidity up. A tip. If you want one for 30 queens, make it for 60. You will be sorry later if you don't. Trevor Weatherhead AUSTRALIA