help with size for breeding pens

[jimmythechicken]

i am going to be building 3 breeding pens for our orpingtons.i already have 3 runs set up they are 9ft wide by 20ft long.how big should i make my coops for 6-7 orps in each coop.thanks for any help or ideas

 

[10 point]

In my book it says to have 1-2 square feet inside per bird and about 10 outside per bird. so 6-14 inside and around 60 outside.