You all have some great setups. Mine is in a state of flux, with 2 main semipermanent structures where most of my mature layers are.
I have a
litterbox (covered and waterproof, they love that,)
a
wooden box (antique)
several plastic milk crates (cheap, but not heavy enough, have to be weighted or tied down and if on the ground have something waterproof so the inside stays dry; I put two high up on a shelf and secured them there, but like BYCforlife mentioned, that's not good for hatchlings; neither is the wooden box nor the litterbox when they are new, b/c they can't get out.. the crates have holes so they can jump back in easily. from the floor. or ground.
My favorite boxes are the ones I made into my truly mobile coop which my bigger half was certain would collapse under the weight of itself. I made the mistake of putting caster wheels on it, which worked beautifully before the unprecedented summer rains set in. The structure itself is solid as a jungle gym, but my wheels were a dismal failure; I'm reduced to moving it with a large pvc pipe, but with some effort, I can still move it by myself.. The boxes came as a result of quandary over what would be the cheapest (as I had already spent too much money on wood and hardware) and add the least amount of weight. I had bought a large roll of hardware cloth that I didn't use on the project, so I cut the mesh and bent the sharp little spikes basket style in two rectangles.. I was making it up as i went, so it's not as neat as I would have liked, but it wasn't bad. The idea for the top was stolen from a prefab coop at
tractor supply that had the hinged lid at the top and the boxes and openings to the outside so you don't have to enter the coop to collect the eggs. The inside opening is next to a perch; ideally they will roost on the perch, and most did before I moved them out and moved my babies in. One or two prefer to roost in a nest though, so it has to be cleaned. My youngest layer, Raja, loves this nest. It is easy to clean; I use dried mowed grass for all my nests in the summer and fallen leaves when the grass isn't growing. These nests are not intended for broody hens; if that happens, I will have to address the issue.
Here is one of the boxes before I divided it into 2 sections (there is one on each side of the back, for a total of 4 nests.) I accidentally deleted the other photos, but the second shows how I wrapped the tines. They are very sharp and will cut you if you aren't careful, but I chalked that up to extra predator protection. I keep the top part plus most of the basket covered with a tarp for summer; will have to winterize soon enough.