I have read through several threads and come to conclusion many here say no heat is fine and maybe even better. My boys raise meat chickens for show. The project lasts approximately 5 to 6 weeks. We purchase 200 chickens. Papers we receive say to maintain temps at 90 degrees for first week and drop it 5 degrees each week thereafter. This is a challenge. We have used 250w heat lamps to get somewhere near these temps. If we were just raising chickens for us, I would not worry about the heat, but I have learned that ventilation, temp., space, water, and feed are all essentials to even be able to compete with others. We just have not figured it all out at this point. Using the heat lamps is fine, but it sure runs an electric bill up in a hurry. We are also told to keep lighting on them 24/7 to encourage eating, but I have also heard turning lights off and letting them sleep will produce a better bird in 5 weeks. Who knows? What is a good source of heat without lighting for 200 birds in 400 sq. ft. (approx.)? Everything I have seen or read is for smaller areas, and I have not found anything that gives even a suggestion of temps. at 90 or so. Also, if anyone has any pointers to raising broilers for show, I am ready to learn. If you have somewhere you can direct me to learn more, I am ready. There is so much as protein in feed, leave them on starter whole time, switch with a completer half way through, use fermented, do not use fermented, turn off lights, turn on lights, use vitamins the whole time, use them only for a week, and the list goes on. Any help and/or direction is appreciated.