how many hens max can I overwinter with my setup?

[TDM]

I think you would be fine with two square feet coop floor space per bird in your colder climate. It help keep the coop warmer if there are more birds per square foot, and helps keep any eggs from freezing. Rarely at one time are the birds on the floor anyway; some are roosting and others may be laying, eating or drinking.

We personally have over 250 birds at two square feet per bird. This minimum space requirement is dictated to us be the stores we sell to, and our flock is unaffected by it. Of course, our run can be considered infinite. A typical 8' x 16' mobile unit shown below houses about 65 birds:

 

[NYRIR]

My coop is 12 x 7...I house 40 birds throughout the cold winters here in NY.I have more than enough roosting space as I have 2 full roosts that aren't used much at all.I also have 2 plexi-glass covered large windows with a roost in front so they can watch what's going on outside.I have had no pecking issues.I do however shovel a good area (roughly 12x12 at least)for them to roam during the day.They also roam the paths we shovel between coops and runs.I also give them things to "peck at" including,flock block,heads of cabbage,shiny tin plates on a string hung at head level.If it's going to be especially cold at night,I cook up some oatmeal for a snack before bedtime.I do feel however,that I am pushing it....and hence the need for entertainment during the winter.I should also mention they come out during the day no matter what the weather.If it's snowing really hard,they hang out under the coop which is elevated about a foot off the ground.They have 3 feeders available and I have a heated base waterer,so the water is always available, which helps so they don't get stressed from that.Honestly,I think it bothered me last winter more than them....I was so worried about them being bored!

 

[TreeHugger]

I've got an 8' x 10' coop with a 30' by 40' run. Last winter I made it through with 30 bantam hens (mainly silkies) and 20 assorted pigeons. During good weather this set-up was fine since most of the birds stayed in the run & only came in the coop at night to roost. However, during the weeks of bad weather/snow the birds did not want to go outside, I didn't see any behavior issues but the coop was a complete mess. I decided I needed to reduce my flock or build. Coop #2 is almost completed and it is 9' by 7' with a 30' by 40' run. My flock is staying the same size & I'm actually looking forward to next winter.