How many chickens are you planning to have? The minimum recommended is 4 square feet per bird inside the house and 10 sq ft per bird outside in the run. These are minimums and I've found from experience that the more room you can give them outside, the better. I basically have a three tier system: Playhouse coop - 100 sq. ft. run - big backyard.
In Minnesota, you may want to build a house on the small side so that they can keep warm for the winter. I live in Colorado, built a playhouse coop, 4' x 6' x 4.5' and a 6' x 10 ' run for six standards. The run is covered and tarped to keep out the snow. They've had the run of the yard for most of the day until yesterday when I built an additional 10' x 10' extended run. The house is insulated with an oversized internal nestbox and roosts for them and they can stay pretty snug in the winter. In summer, I'll open windows and vents. This is pretty much the house. Since the run is covered and has an underhouse area so there's places for them to be dry. It works really well.
I mention this because the original coop was as predator proof as I could make it. Even though I live inside a town, I've gotten racoons in my yard and I feel confident in the security of the system. I close them up at night with latches and catches.
The big run was added because I was tired of the dog tracking mud and chicken poo into the house every opportunity she could. They only use it during the daytime and I'll let them back into the yard for an hour or so when I get home from work. I'm hoping it will cut down on the holes in every garden, poop on every available surface and the general destruction that comes with having happy, healthy chickens. In addition, with spring on the way I'm afraid that the girls will yank out and eat any green shoot trying to come up, poisonous or not.
I looked at a lot of coops in this section for weeks before I decided on my design. I am very happy with the playhouse coop.
Good luck.