Welcome to BYC. If you put your general location into your profile people will be able to give you better-targeted advice when you ask questions.
Generous space is not a problem. Chickens benefit from having plenty of room to move around and do chicken things. My 2-week-old chicks use every inch of a 4x8 brooder.
20F is not cold to a chicken. They wear built-in down parkas and tolerate cold much better than they tolerate heat. They key is good ventilation, which removes excess heat in the summer and excess moisture year-round.
https://www.backyardchickens.com/articles/hot-climate-chicken-housing-and-care.77263/
https://www.backyardchickens.com/articles/repecka-illustrates-coop-ventilation.77659/
Generous space is not a problem. Chickens benefit from having plenty of room to move around and do chicken things. My 2-week-old chicks use every inch of a 4x8 brooder.

20F is not cold to a chicken. They wear built-in down parkas and tolerate cold much better than they tolerate heat. They key is good ventilation, which removes excess heat in the summer and excess moisture year-round.
https://www.backyardchickens.com/articles/hot-climate-chicken-housing-and-care.77263/
https://www.backyardchickens.com/articles/repecka-illustrates-coop-ventilation.77659/