I have not been using a thermometer in the brooder with the chicks, I have just been watching their behaviour, and adjusting the temp. accordingly. I have a 250W clear heat lamp wired onto a dimmer switch, so that the temp. can be adjusted without moving the lamp around. What I would like to know is how others who do not use a thermometer in the brooder go about lowering the temp. each week? Do you just watch the chicks, and they'll let you know when they are ready for less heat? The book I have says to start at 32C and go down 2-3C each week until you reach 20C, at around 6 weeks of age. Any thoughts?