It is difficult to calculate how many heat lamps you will need. You need to set it up and test it BEFORE you have the chicks. When I setup a brooder last spring I was sure that one heat lamp would be enough. I setup the brooder, put in a couple of inches of wood shavings, and covered them with paper towels. Then I turned on the heat lamp for a few hours. The temperature was only 78 degrees.I covered part of the top of the brooder (away from the heat lamp with plywood. This got the temperature up a little but not enough. I decided then that I needed a second heat lamp. That did the trick.
It is important to setup the brooded just like it will be with the chicks. At first I tried testing it without the bedding material. The temperature was all over the place in different parts of the brooder (I used a big steel tub sometimes used for large livestock watering). The bedding really helped even out the temperature.
This year I am probably going to use a wood brooder instead of the steel tub for my new batch of chicks. I suspect I will only need one heat lamp in this setup but I won't know until I test it. I won't be getting chicks until early April and so I still have lots of time to set it up, test it, and make adjustments as needed.
It is important to setup the brooded just like it will be with the chicks. At first I tried testing it without the bedding material. The temperature was all over the place in different parts of the brooder (I used a big steel tub sometimes used for large livestock watering). The bedding really helped even out the temperature.
This year I am probably going to use a wood brooder instead of the steel tub for my new batch of chicks. I suspect I will only need one heat lamp in this setup but I won't know until I test it. I won't be getting chicks until early April and so I still have lots of time to set it up, test it, and make adjustments as needed.