Unfortunately, the lump feels hard, so it doesn't seem like a breast blister. I took a couple more pictures, but they just don't get the point across very well...
So this chick will be 1 week hatched tomorrow. This MASSIVE lump appeared just yesterday. It is in the neck region, but off to one side. She is eating and drinking, though she seems like she may be a little more lethargic than the other chicks. She is a bit smaller than the other chicks as...
Very clever indeed. And if those boxes were set on tables or simply given legs (depending how it's supported below), you effectively increase the square footage in your run, provide new roosting spots, and provide extra shade. I like it.