$30 Dollar Budget Brooder

Very nice.

Kudos to your project!!

I too had that same issue when I first moved to a farm and we decided to raise layers and cornish Xs. I also used your approach, but due to the amount of birds being raised, kept our demensions at 4x8x2, then after the first batch, reduced the size to 36"x96"X18", which still contained the chicks.
Next, we decided that due to the amount of natural fertilizer being produced, and the HUGE amount of time replacing newspaper, and later other material, I changed the bottom to 1/2" hardware cloth stapled along the edges, and did add a 18"x36" partition in the middle of the brooder, along with 2x2 supports in the bottom of each new half. Next, we then raised our brooder on cinder block standing on end, which provided easier access to the flock, without ending up stooped over so far our back hurt, or down on our knees.
The wire bottoms proved to be a huge success, as the fertilizer now just dropped down onto paper on the floor, which was easier to maintain. One would think that chicks at 2 days old wouldn't be able to walk on 1/2" spaced wire, but we had no issues with broken legs, and 1/4" wire didn't allow enough to drop thru and made for messier clean up.
I ended up with 3 of these brooders in the barn, which allowed us to rotate flocks, and clean up between batches was done with a pressure washer.