My horse, donkey and mini donkey are outside 24x7. They have a deep run in. I am in SE SD, so very similar to MN and IA, which are a stone’s throw away.
I ran electricity and water to my drylot (where the shelter is). My farm light is also over the drylot. I can add additional light easily, or use the garage (mat it) for the vet.
The other big factor is my shelter belt, assuming a north or west wind is about 100 feet deep and mature. It has been awesome. Except on the random south wind days.
I need another run-in stall for layups and I am planning on building a tack room in-between (so connecting the three). However, that won’t happen next summer. Next summer I am building a tie-stall/wash rack, doing more fencing and my manure bins. I think I will board my riding horse next winter and keep her in training, but this type of cart helps: http://www.sstack.com/Stable_RacksOrganizers_Saddle-Racks/Easy-up-Tack-Room-On-Wheels-08174/?green=7FD433C0-29DB-5E12-069F-C69299C0EB09
Instead of a barn, I want to build a machine/toy shed, but would allow an area for vet work, etc. Then add onto my house garage with insulation and heated water out there. This is better resale in my area.
Of course I would love a barn. But I’m doing a lot less chores than my barn-friends. I also only have one, young horse who has always lived outside and isn’t in training, clipped or even blanketed.