I'd stick with wood, but use either treated, redwood, cedar etc... they'll hold up alot longer.
I might stick with wood, I'll have to see. If I do, I'll probably go with pine to keep it light, even though it will rot faster. I'll see how long it lasts with that and maybe a coat of paint on it, then consider upgrading to something longer lasting. It all depends on how well the chicken raising is going.
Don't get cockerels unless you plan on butchering them.
From the place we'll get them, they're not sexed. If we end up with boys, they'll be gone one way or another

I'm not keeping them around. I might prefer a male duck though, I don't really go for duck eggs.

the predators we have problems with are racoons and hawks. Racoons mostly at dusk and at night. We have not found an enclosure that is truly racoon proof.
Thanks Bruce. I've heard the chickens will often scratch the larger slugs, so whether they eat them or not isn't so important

We have some bald eagles and bobcats in the neighborhood sometimes, they might go for a full grown one. Maybe not. The coyotes are regular visitors though. I rarely see raccoons, but that doesn't mean they're not there. I figure as long as I remember to lock the chickens up at night they should be ok. Or not. We'll find out

tom, you must be a small guy
Most would not say that, but maybe I'm just bad at estimating length. Guys are supposed to over estimate length though, right?

Mom and Dad would order around 150 chicks each Spring
Feeding an army? Where do you keep 150 chickens once they're slaughtered? Did you just have a huge freezer?