difficult decisions, they like to be together in a flock but they do not like to be overcrowded, you will have to watch and adjust. Lower chicken numbers or increase pen size depending on how they get along
here is my chicken math:
an acre is 209 feet by 209 feet = 43681 square feet
if I can stuff in one chicken for every four square feet and I have 41 acres
(43,681/4)x41=447,730 chickens on my place without building a second story