Hi Alan! Welcome to BYC! I would echo the "no" on the sawdust. It will cause respitory issues. Also if you do purchase shavings, make sure they are NOT cedar. The oils are toxic to chickens.
We have an 8x10 shed that we converted into our coop and we have 24 hens.
Here are the nest boxes...
Roosts...
Our floor had some issues too, so we just covered it with new plywood.
I also use DE. It's really important to get the right stuff, because the wrong stuff will kill your birds. Make sure it says "food grade". The DE keeps the mites and other creepy crawlys away, it contols moisture and keeps the odor down. When you mix it in their food (2% ratio) it helps control internal parasites as well. It's wonderful stuff!
One of the bigest things to keep in mind when constructing your coop and run is preditors. Learn from the mistakes already made by our group.
Interesting....I sound like I know what I'm talking about! I am new to being a chicken mom too. I learned everything I know from the friends on this fourm! I've had friends that have had chickens for years comment on how great my girls look and ask how I keep them so healthy and such. It's all do to the combined and generously shared knowlage of the people on this forum.
Beware...Chickens truly are addictive and so is this forum.