I need to get started on building a brooder for my chicks that are supposed to be arriving in like a week and a half. I have time to do it today but I need to know what size should it be??? I don't want to have to build a bigger one in a few weeks time so I'd like to be able to leave them in it until they're ready to go outside. I'm getting 31 chicks - a variety of chickens - Wyandottes, Araucanas, Blue Andalusians... Just so you can get an idea of the sizes. Help would be greatly appreciated!