Welcome to BYC.
Where, in general, are you? Climate matters, especially when it comes to housing.
Here are the Usual Guidelines as a starting reference:
For each adult, standard-sized hen you need:
- 4 square feet in the coop (.37 square meters)
- 10 square feet in the run (.93 square meters),
- 1 linear foot of roost (.3 meters),
- 1/4 of a nest box,
- And 1 square foot (.09) of permanent, 24/7/365 ventilation, preferably located over the birds' heads when they're sitting on the roost.
Yes, you want to avoid drafts, but that doesn't mean closing the coop up because generous ventilation is one of the keys to keeping chickens healthy. Take a look at my brooder, which is 4x8, has 16 square feet of permanent ventilation with 10 square feet of supplemental ventilation, and still needs shade to prevent temperatures from exceeding 100F on days over 93F.
After 4-6 weeks depending on breeds and conditions,
chickens do not need supplemental heat except in the most extreme winter conditions. They wear built-in down parkas and don't even notice the cold until it gets down around 0F. If you do live in an extreme climate, you'll want to read this article:
https://www.backyardchickens.com/articles/cold-weather-poultry-housing-and-care.72010/
What they need is to be protected from roost-level drafts that are strong enough to ruffle their feathers and thus disturb their natural ventilation.
6 feet is very high for the roosts. Is there a particular reason that you've chosen that?
In my new coop I specifically set my roosts no higher than my own shoulders so that I can easily tend to them at night and so that when I'm in there working no chicken will be sitting with it's eyes above my eyes -- because dominant bird perches highest and I learned from keeping cockatiels about the importance of respecting this.
Most of my birds easily fly up and down from those roosts but some take it in stages, hopping from the 18" juvenile roosts, and the Brahma can't fly at all so I had to make her a ramp to get to both the roosts and the nests.
It's possible for a heavy bird to injure it's feet/legs jumping down from a high roost. Additionally, chickens tend to fly at a 45-degree angle and most of them fly more like C-130s than like F-16's, so if the roost is closer to the wall on the dismount side than it is high they may crash into the wall or wire and injure themselves.
Pine shavings are fine for chickens. Fresh, GREEN wood with the sap still in it can support the growth of some toxic molds, but the dried shavings that are sold in the farm store have been proven safe over many years and millions of users. People claiming that pine shavings are dangerous are usually trying to sell you something else.
Cedar, however, is a different matter. Western Cedar, such as
@rosemarythyme uses, has much less of the aromatic oils that make Eastern Red Cedar valuable for protection from insects. Those oils, however, are irritating or even toxic to birds -- who have extremely delicate respiratory systems (remember the canary in the coal mine thing?).
