Apologies if you’ve been raising chickens forever, but are you new to chicken-keeping? And how old are your current 7?
Many new chicken owners go out too big, too soon. There’s a lot to be said for holding off until your current ones have been laying a while and everyone has a nice rhythm going. A year old, in other words.
For one thing, if you loaded up on the maximum number of chickens now, what will you do in 2-3 years when there’s a good chance that a substantial number will stop laying? If you wanted to get new layers then, would you soup the older ones to make space? There’s a lot to be said for starting with your 7, then adding five more next year, then five the year after. Sadly, chickens do “up and die” without warning at times, and a schedule like the above will allow you to add on gently.
General size recommendations:
4 sq ft per bird MINIMUM in the coop (house); maybe more in you live in an areas that gets extended bad weather (snow, rain)
1 linear foot (along the roost poles) per bird
10-15 sq ft per bird in the run
Chickens shut up in too small a space in bad weather get cabin fever very quickly and can become vicious to one another, even cannibalism.