Homeade incubator help

I had a home made incubator for my first three chicks. You can get different temperature bulbs but I just moved the lamp closer or further away from the box depending on if they was cold or hot then further away as they got older and off for a little bit building up to just being on at night by the time they was 4 months. if they are hot they will pant and huddle as far away from the lamp as possible if they are cold they will huddle together as close to the lamp as possible and maybe shivering