Most people don't have a brooder in their barn, but they look sort of like little flying saucers made out of galvanized wash tubs. Brooders use incandescent light bulbs to warm the little birds, so may be on the way out with the adoption of energy saving compact florescent bulbs. Small birds are very delicate especially when it comes to temperature, and Spring is notoriously unreliable in the weather department. Some folk, especially the hippies, would bring their brooders into their kitchen for a few weeks. Baby poultry has a not unpleasant smell that is easily identified. As a volunteer fireman I had occasion to visit people's home in the wee hours, and would look to move the chicks to a neighbor's house if I smelled that "eau de peeper". Chicks can't take much smoke.
It's funny the things that goad memories up out of the depths, and Spring elicits some of the most pleasant.