Buy the best you can afford and for long term use stay away from the Tractor Supply types (they don't hold up)... many of us convert the 'amish type' sheds for durability and versatility. Full height sheds allow easier human access for cleaning but the smaller ones are easier to tuck into the corner of a yard, so your situation should determine the best fit for you. In Pa. climates I prefer the 4 ft per bird inside the coop and 10 ft per bird outside. During harsh weather the birds may literally be 'cooped up' for extended times and being crowded isn't good. Plan for about twice what you think you will want since most folks end up with more birds than they originally planned, lol.
The outside run construction should be done based on the predators of the area...chain link or heavy goat fencing is good with smaller hardware cloth around at least the bottom 18" is good with either heavy bird netting or chicken wire over the top. If you live near weasels or mink you will want to consider the hardware cloth over all of the sides and top since the can get through very small openings and they climb well.
For daytime free ranging you can create any type of fencing that will stand up to neighborhood dogs and either use poles to hold up bird netting for hawk protection or make sure there are plenty of places for your birds to hide under if they see an overhead threat.
There are no 'predator proof' set ups, but you can minimize losses by planning for 'worst case scenarios'.
Ducklng was insistent that we need more ducks today.
You are evil.
