Eighty to ninety will work if your brooder is big enough. I use a red heat bulb. Some say it will keep the pecking down. They will seek there own comfort level. You'll drive yourself crazy trying to keep it at the exact temp. I got seventeen two day olds, in yesterday and they are moving up close to the lamp and then they back off all day long. Eating, drinking, pooping scurrying around and sleeping I'm going to put a small tree limb in next week so they can perch and play. I look at there eyes for a sign that they are getting sick or some other problem. One quick suggestion, keep there butts clean or the pecking will start. This batch seems to be more active than any I have had. You are in for a lot of fun. Good luck. Franko