What would be a good size run for 3 hens?

I've got 4 in a tractor that is 6' X 8', about 1/3 is the roosting area and the rest is screened in as a run (they can move about under the roost and nest box). According to the numbers, this should be okay BUT--it looks small to me. I let them out every morning at dawn and close them up every night at dark. I have feed and water freely available from hanging feeders/waterers inside and water available outside, so it's not strictly a run. As for size--make it as big as you possible can. Even if you are restricted legally as to how many you can have and how freely they can range, there will be times they are stuck inside and you want as much room as possible.

 

The bigger, the better. If it is too small, they will strip mine all vegetation. At a minimum, go for 10 sq feet per bird, but they will be much happier with as much space as you can give them.

 

8'x8'x36" high. Cover 1/2 of the run with 1 sheet of 4x8 plywood.

 

I also have three hens - coop is about 7 x 4 x 3 1/2. I see the point about bigger being better if the chickens are stuck inside but doesn't it need to be small enough so they stay warm since there's only 3 of them? Our run is 13 1/2 x 7 1/2 and we let the girls run around the backyard a bit every day (not too much due to 2 dogs and a raccoon that likes to visit). It's our first year with hens - they seem really happy with their run. They're Wyandottes which I think are a very mellow breed.

Do you mind if I ask, how are you heating your coop for winter?

(Pip, Chirp and Gladys)

 

Mild winters here, not planning on providing any heat, maybe a blanket over the hen house if it gets really cold (high teens to low 20's are uncommon, it rarely gets below freezing)