Weasleymum, I agree with you on the very small coops. However, if your coop is 3.5' tall or more you can elevate the nesting boxes off the floor and you don't lose floor space for your chicks to walk around on. Interior nesting boxes will stay warmer during the winter months because they will get more heat from the other chickens inside the coop. I elevated my nesting boxes 16" off the floor of my recently completed coop as I wanted all of the 48 SF floor space available for my dozen chicks. Provided the nesting boxes with a perch so they can flap up there and inspect where they will lay their next perfect egg. Hope it works!
Doug
Here are the four nesting boxes, elevated 16" off the floor, before I put my plywood on the outside. They are 16" long X 11" wide with almost 2' of headroom under the sloped cover. Left a gap above the sloped cover for ventilation. I used some repurposed cove molding for the front perch.
Here is my coop finished and painted. The four openings on the left are my egg collection holes.
Ohhh, that is really cool. Kind of the best of both worlds!