Welcome to BYC. Glad you decided to join our flock. Chickens can not only turn a patch of grass in a run into a dirt bed in a couple of days; if you get any rain, they can turn the dirt bed into a mud hole in no time at all. I would put either fine pea gravel or coarse river sand with varying sized pebbles in it in the run. Also, if you can put a roof over your run to keep the rain off, I would do that as well. Pine shavings (not chips) makes a perfect bedding for the interior of your coop. Feathers are excellent insulators, so I wouldn't put a light in the coop, but you do need to make certain that it is draft free with no leaks in the roof or walls. Moisture is a far greater danger than cold. Please feel free to ask any questions you may have. We are here to help in any way we can. What kind of chickens do you have?