I don't use cardboard boxes. The brooder I posted is where they go from the moment they arrive home until about 2 weeks, at which point they get full access to coop and run during daytime.My plan is to get 8 chicks, what size cardboard box you I construct for them and when do I allow them to have access to the inside of my trailer coop?
More about my outdoor brooding process (most of this is integration but there's still photos of the set up): https://www.backyardchickens.com/articles/short-on-time-recycle-a-prefab-brooder.73985/