what's the best setup for a chick brooder?

First Question...... How many chicks are you planning to raise???
The cardboard box idea is not a bad one. You can use a plastic tote tub as well. The key to keeping things dry is pine shavings on bottom. You do need to replace when soiled and/or wet of course. Use waterers that will not tip over easily. Place pebbles into them so baby chicks do not drown in...... Marbles work also.
Have container large enough so there is now crowding, and also provide heat at one end of the brooder. Reason.... So there is enough room for chicks to find a comfort zone... Not too hot/ not too cool..
WISHING YOU BEST..

 

There's no law that requires you to brood in a box. You may choose to brood out in your coop or run in a safe pen instead. The advantages are numerous. You might also consider using the heating pad system instead of a dangerous heat lamp, further increasing the advantages.

I finished an article on this subject just in time for chick season, and I go over all the reasons why brooding outdoors is superior to doing it indoors in your house.

Click on the link below under "Articles by azygous" on tossing out your indoor brooder.

 

I chose to make a brooder/tractor for my first brood of chicks. It's 3 x 6, with a door that opens in the top of each end. I later installed a door on one end. This makes a great brooder, as well as a broody day time play pen, and a nice little tractor to keep chicks safe from hawk predation. IMO, multi purpose is the way to go. That little tractor has paid for it'self a dozen times over. I later made a larger one, 6 x 8 that can be used for a rooster grow out pen, to handle a larger # of chicks, and can be used for a winter cold frame.

 

I used a large dog crate that we had - took the top off. When they got larger, i turned the top over and placed them end to end to double the space they had. It's worked very well