I'm working on designing a brooder that can stay out on the pasture all year round. It would only be used for a few weeks a year, but would have power and water lines going to it (or at least a good outdoor rated extension cord, and a frost free hydrant near-by). Saw some pictures that looked good, but no plans. So I'll have to sketch out some plans of my own. This would be mostly for broilers and turkey poults. But it could be used for pullets if I wanted.
Having kept the chicks either in the house, or the detached garage, for the last few years I'd like to not do that again. Between the dust, smell (which doesn't bother me as I can't smell it, but the rest of the family can), and mess it would be really nice to have that all outdoors.
Plus, I figure with the broilers I can get them on grass a lot sooner. The pictures I saw included a ramp that could be lowered to get the chicks access to pasture on good weather days when they're as young as a week or two. That gets them used to foraging much younger than otherwise, and it gives them more room to do
chicken stuff. Plus the fresh air, and opportunity to
poop outside the brooder
should all help with their health.