Brooder
I asked hubby to make me a brooder as we used a cardboard box he made. (Above). The holes allowed the heater outside of it to let heat in. If it got too much, they had the whole other side of the box to cool down. It worked pretty slick for a while, but I wanted one bigger and at eye level instead of a box on a TV tray.
I showed him the brooder pictures in the brooder forum on BYC. He spent a lot of time going through, picking out good points and bad points he saw and considering things I wanted, such as the height and a hinged door that locks open. He drew it out and came up with this. On top is our adopted barn cat Stella, who decided she should be in the house to watch the chicks.
It is 62" high and 24"x36". The bottom of the brooder is 28" from the floor.
He wired it with an electrical box on the back top corner of the brooder and an LED light bar on the ceiling of it. The light has a switch outside on the brooder so we shut it off when they're sleeping. They get used to darkness this way. The heat lamp is a black ceramic bulb in a cover rated for such. The heat lamp plugs into the thermostat. We found having the thermostat helps keep the temperature steadier. It's an Inkbird ITC-306T. We've had it for three or four batches of chicks and are glad we have it.
We lined the bottom of the walls with some leftover linoleum. If you build one, consider doing something like this to make cleaning easier and protect the wood.
We made the brooder a nipple waterer. The coop has a 5-gallon bucket with nipples like this, so they'll already know how to use them when they transition to the coop. Hard and thick plastic works better. This is an old Tupperware cereal container. You can get the verticle nipples on Amazon. We use a horizontal nipple bottle for water for their first two to three weeks, then convert them to this.