Hey. They are 3 Rhode Island reds, 1 welsummer, 1 Americana and a Colombian mixed.
So 6 chickens, that means:
24 square feet in the coop -- so 4x6. 4x8 would be just as easy to build with no cuts required on the wall sheathing since it comes in 4x8 sheets.
60 square feet in the run -- so 6x10. 8x8 would, again, be easier to build since lumber comes in multiples of 4 feet. Hardware cloth is commonly available in 2-foot, 3-foot, and 4-foot rolls.
6 feet of roost,
2 nest boxes,
And 6 square feet of ventilation in the coop. 1 square foot is 1 foot wide and one foot tall. Or 2 feet wide and 6 inches tall. Or 4 feet wide and 3 inches tall. Or a triangle under your gable peak that is 2 feet wide at the bottom and one foot tall.