I can't think of any cons. Perhaps the cost of hardware/doors. That's it.
I would recommend about a 2 foot overhang. It will help keep water out of the barn, away from the foundation, and cut down on direct sunlight in the heat of summer. It's not required, but if you're building a barn from scratch why not go for it.
My barn has a concrete foundation. I have mats in the stalls. No problems with moisture or rodents.
I don't recall my insurance company giving me a break on the premium - what mattered to them was having wiring in conduit and storing hay and other combustibles away from the barn. But in an emergency (including things like cast horses) you are going to be glad you have that outer door.
Brothers and sisters, I bid you beware
Of giving your heart to a dog to tear.
As someone noted above, the only con I can think of is if they are installed or sited badly, which is a con to any sort of construction. Note: always make sure outside doors are latched so that they can be opened *from the outside* - otherwise they do you little or no good in case of fire. (We have dutch doors where the top unlatches on the inside and the bottom on the outside, so both are accessible from either side should the need arise.)
I have front and back doors because we built the barn in the middle of two pastures. This way, it's easy to rotate grass, separate a horse if necessary and clean stalls without the horses "helping". Love 'em.
Love my outside dutch doors for: safety, convenience, ventilation, appearance, gives horses more room in the stall and more interest and socialbility when stalled. Only downsides I can think of are the added expense and if the horses were to chew on the outside of the barn, not something that has happened with mine. The first three things on my pro list absolutely outweigh the cons. We have a 10' overhang, so the outside of the stalls becomes a shedrow set-up and the inside doors open into a center aisle. Best of all worlds.
I just built my barn and love my back dutch doors. My horses love to hang their heads out of the stall and they are great in the hot weather. The cross breeze creates constant ventilation and helps keep the barn cool.
I am building my barn right now, and I researched these questions pretty thoroughly before starting. I did put outside Dutch doors on all 4 stalls. There is a 12' overhang which will give the horses shade and some shelter from rain so they can stay outside if they want while it rains or snows. The stalls open into a sacrifice paddock, which I am contemplating subdividing or setting up to be easily subdivided on a temporary basis should I need to do that at some point in the future. I am in a cold climate, so I do not expect to be keeping the doors open a lot during the winter. But for the rest of the year they hopefully will be super convenient. I got pretty expensive doors - they are steel framed, which hopefully will reduce chewing and warping.
The exterior of the barn will be clad in board and batten hemlock on the sides where the horses would have access to the siding. I chose this because it will not dent or crack if kicked, and if a board is in bad shape it is really easy to replace.
In the stalls I am putting crushed stone with rubber mats on top. My neighbors have wood plank floors in their stalls which have to be replaced every few years. To me that's kind of a pain so I'd rather fork out the money for mats at the beginning and then not have to deal with replacing things for quite a while.
I'd say paddock stall doors are a big plus!! Air movement is another pro I'll add. I do not have to lead horses out to pastures. Stall doors open to dry lot - from there I just open gates to the pasture I want them in. Stalls act as a run in if needed.
^^This. We are set up the same way in 2 of our stalls and it's especially useful if you have a broodie and new baby, or two newly weaned foals, that just need fresh air and sunshine in a paddock, not the liberty of a whole pasture. In a pinch you can even double up two amenable adult horses in the space.
As far as footing, we have bluestone under stallmats. Huge savings in both shavings and time to clean. Never had any drainage issues either, although once in a while we'll get a mouse move in under the mats and have to put some poison down under the mats.
In addition to all that have been mentioned, I also found that being able to allow the horse to hang its head over to "observe" the scenery through the back door (if it is the dutch door style) seems to help some nervous horses.
The only con side is the extra expense of framing and putting up extra doors.
The extra doors are indeed an added expense, but if we can build Dutch Doors and hang them, anyone can LOL Ok, we aren't that bad, we have all the tools but really, it's not that difficult. I had the exterior doors framed when the barn was built, and in the grand scheme of even just the shell of the barn, the extra posts were not that big a deal. I just used chains for quite a few years, inside and out, and only got around to actual doors when my mare was close to foaling.
Love, love love exterior doors.
______________________________ The CoTH CYA - please consult w/your veterinarian under any and all circumstances. - ET
Having doors front and rear of the stall was a huge benefit when we built our barn. Safety wise, the peace of mind to be able to get them out easily is huge. You won't regret adding them in if you are building.
We love ours but we have one horse who will 'blast' out of his stall on occasion so make sure the human helper has side room 'escape route' when opening the door from the outside (hinge door). Or build a sliding door.
(I know, I know, train the horse not to blast out but it's not my horse and is just a 'fresh boy' on occasions of long periods of stall time)