Small Barns and Shelters
Blackbelly's need very little in the way of extravagant shelters. Simple and open structures provide relief from the sun and/or rain and the addition of a small wall adds a wind block from a cold winter breeze.
There are much more elaborate plans worth investigating before building larger barn structures as your needs may vary depending on what your goals are and what your pocketbook can afford. Of course, it seems that the longer you're raising sheep the more you'd like to have and do. But if an inexpensive shelter and easy project is all you want then perhaps this page will be all you need. You can make these in a weekend.
For those of you looking for more in the way of plans and seeking what the professionals do, and I mean MUCH more, then you might want to visit the North Dakota State University Extension Service which has many drawings to look at for specialty projects and barn layouts.
Additional layouts and plans can be found through:
Farm Buildings: A Compilation of Plans for General Farm Barns
Housing Your Flock
Canada Plan Service - CPS 4000 Series Sheep

An interesting, and inexpensive, book of interest might be:
How to Build Small Barns & Outbuildings
by Monte Burch
Workman Publishing Co.
1992
ISBN: 0-88266-774-2
Some of the things you may consider in your plans,
not necessarily covered in this website, include :
a) Storage (feed, halters, grooming, minerals, salt blocks, tools, ...)
b) Separate stalls for quarantining sheep, pregnant ewes, bummer lambs
c) Door/gate layouts for capturing selected animals
d) Materials of construction
e) Concrete, dirt, stone or dirt flooring
Lean-to
The lean-to is the most basic and least expensive design of any shelter; all in about $150 if you buy all new supplies. When we think of lean-to we think about sticks leaning on two posts that suspend a horizontal stick and keep people out of the cold for the night. You can do that if you like but my idea of a lean-to takes it to the next level of permanency by sinking posts and installing a tin or asphalt roof; tin being less expensive, readily available, and far easier to install -- easy is good.
Corrugated tin (or plastic) is typically available in sheets of 2.5 x 8 feet in length. Today these can even be found made of recycled rubbers and colorized in brown, green or red. The recycled rubber panels are excellent products, but they're also about three times the cost; of course they don't rust either.
The simple lean structure is built by first sinking four posts in a rectangle pattern. The depth of the structure is 84-inches as measured from the outside widths of the posts. The width is either 102 or 129-inches (8.5 feet and 10.75 feet respectively) as measured from the outside width of the posts. You can make is smaller but the corrugation will run the wrong way or you'll need to cut the tin down to a smaller size (In the picture above the corrugation runs the wrong way - hard to see but it is). The reason for these dimensions is to allow overhang of the tin across the top edges by at least 3-inches on all sides and to allow 3-inches overlap for each piece of corrugated tin as they are placed and interlocked atop one another.
The joists (2x6) stretch from post to post at a slope supporting the rafters (2x4's) holding the corrugated roofing panels
(Note the slope of the roof allowing drainage)
Notched Post support joists
and are nailed or screwed with lag bolts
The posts should be sunk as suggested in the fence building section of this site and I'd recommend 4x4 treated posts ONLY; 8 foot posts are needed for this structure. Treated posts resist termites and other wood boring insects as well as resist dry-rot and issues related to wet conditions. 4x4 posts are also stronger and are less likely to warp when they dry, and if they do warp, the warp will be minimal.
Make sure the posts are properly spaced and squared with one another like the walls of a room. Posts must be perfectly vertical and twisted to face the right direction. Simple tools such as a measuring tape, string, a small level, and a sharpie marking pen will help a great deal with the project. Dig and sink your first post and once the concrete is dry then all other posts are positioned based on that post -- it becomes the key-stone for the post placing.
When the posts are all placed and the concrete is dry, cut the posts down to 60-inches in the front of the shelter and 50-inches in the back. The different height provides the pitch (angle) for the roof to drain properly. If you live in a snow climate then you may want to consider a steeper pitched roof so that the snow will slide off the shelter and perhaps you may want to provide additional supports (approx. every 4-ft) to hold the added weight of the snow.
Notch the outside facing portion of the 4x4 in both front and back to accept a 2x4 roof support. Pre-drill a hole for a lag-bolt and screw the pre-cut 2x4 across the front and across the back posts of the lean-to (these are the longest beams running the width of the shelter). Again, I suggest using treated lumber for the sake of longevity and bug protection because dry rot will only take a couple years and you'll be doing this project all over again.
Next, cut the 2x4 rafters (running front to back) so that you'll have them spaced about every 24-inches. The spacing is important so that the screws holding down the roof will line up with the corrugation in the roof tin. Laying a tin from front to back will give you the exact spacing. Because of the angle of the roof you must also remember that the ends of the rafter beams will need to be angled slightly to make a perfect fit - don't worry if it's not exact but a tighter fit is preferred. The rafters can be nailed in or you can use exterior screws.
Lay out the roofing tin onto the roof one piece at a time, using self-tapping screws, screw (Not Nail) each piece of tin to the rafters and seal the screw with a small amount of clear silicone calking. If desired, side walls can also be installed in a similar manner. Unfortunately, the problem with any wall will be your ram/s. They like to butt heads with anything that bounces back and that includes tin. But if you install a side rail using a 2x4's at 19 inches they won't think it's as fun (Pictures below). In the lean-to project a beam will not be needed on the outside, just the inside of the shelter so long as the metal is flush against the wood.

Butt boards will help protect the walls from your ram/s. These are about 18-20 inches from the ground.
Note also that the plywood walls don't need to touch the wet ground (Wood should be painted)
Small Barn
The only significant difference a small barn has from a lean-to is that there are at least three walls to a barn; thick plywood or tin are great. The barn is mainly used for protection during stronger winds, driving rain, and during the cold nights. A totally sealed barn, like your house, isn't the idea behind these simple structures and if you need something more substantial then you should probably consider seeking a professional contractor and architect.
As your sheep may spend a significant amount of time in the barn during certain parts of the season they'll often deposit a fair amount of manure and urine. This can begin to ferment and yield ammonia at some point and if you've ever been a little to close to that smell, well, it can be overwhelming not only to you but also your sheep. Give them air for ventilation.

These roof panels were installed incorrectly. Not hanging far enough over the edge of the barn they allow water to drip onto the wood when it rains causing dry rot. The barn needs to be narrower than the roof tiles -- something I didn't plan in advance. You can also see the gap left for ventilation. The sheep actually rest here during the hot summer days rather than in the shade of a tree.
To properly ventilate the small barn the upper portion of the walls can allow clearance for fresh air to enter and exit. Closing the gap against the roof will certainly let the heat out of the building but God gave the sheep a nice winter coat for the cold but didn't give them ammonia breathing lungs. The sheep will do fine in the cold but they really need fresh air that isn't gusting in at them.
Windows for light aren't necessary either. If you use a white or clear plastic corrugated panel/s like the tin (Used above) or simply alternating tin and clear or white plastic. Even a door, a people door, isn't really necessary. Simply allowing a 4-ft clearance on one of the walls will provide the entrance your sheep will need; but choose the side of the barn that typically is opposite the wind.
Roofing is installed similar to the lean-to except the rafter beams can lay atop joists and held down by either nails, straps, or steel hardware you can find at your local hardware store for framing house walls. The joists supporting the rafters are bolted or nailed to the wood posts supporting the structure (in my pics they are nailed but I found that the nails are now slipping)
Stud layout -- This link is overkill for a simple barn, but informative if you've never framed a house.

Wasps love these shelters -- be alert.
Normally they just watch you but if you get too close -- OUCH!