We have been working on our coop for over a month. My husband attends college classes during the day, so he can only work a few hours at night and on Sunday. We bought the book Building Chicken Coops for Dummies. And going by the book really slows you down. My husband wanted to go by the book. My friend and I who have enough experience to build a coop kept telling him the book was not right on certain things. When we were down to raising the walls, he realized that the book had many sizes of boards wrong, placement of 2x4's, etc. And it left out some very important instructions. We had to add to extra 2x4's in the walls, and a few other things. Our coop is almost done, and the chicks in the dog kennels in basement are over ready to go their new home.
To build it it I went through all of the pictures on this site and picked out what I wanted and then sized it to make sure the chickens had enough room. Sketchup is an amazing free tool.
I spent months on the design off and on since it was winter, lots of changing things around but it was worth it since it made buying material and actually building it much easier. Building it only took a while because we're so busy, if I had two full weekends I could do it with the plans.