For the most part, they acclimate themselves. Just make sure your coop is well ventilated, perhaps adding a small solar fan to keep good air circulation in the summer. In the winter, just make sure they have plenty of bedding and adequate roosts, and that there are no drafts in the coop. The coldest I've ever dealt with is -15F but most northerners on here never use lamps in even colder temperatures!
Though I do give mine some frozen fruits and veggies in the summer and warm veggies in the winter, just for comfort. It's a nice treat!
My vents are in the top of the coop, creating air exchange far above their heads where it will not touch the birds. The fan is facing outward, as to push hot air out, rather than having the air flow hitting the birds. Sort of like an attic fan.I've seen a few recommendations in this thread about adding fans for the chickens. Where would you position it? I guess I would have thought a fan could cause a draft and would have been afraid to use it - but still coming to terms w/ the difference between "ventilation" vs. "drafts". (Newbie just trying to learn...)