Four weeks, 18 chicks (but 6 are silkies, don't eat much) and have gone through less than 10 pounds. I don't let them waste anything. If I find lots of stuff at the bottom of the brooder when I'm cleaning it out they get to pick way at it until it's cleaned up.
I use a disposable incontinence pad at the bottom, then a sheet or two of newspaper, covered by paper shreds (from the office shredder at work). I only use a bit of shreds at the end of the brooder where the feeders are. I put their roost bar on the floor to hold back the bedding. I use the typical round mason jar feeder, put it in a pie pan to prevent loss from billing out, and put it up on a brick as the birds get taller. There is very little waste in the brooder.