LSU AgCenter has this free barn plan that's for a 20 X 30, two-story barn with a 10 foot wide lean-to.
This PDF file shows several drawings of the barn from different perspectives, all with measurements and short descriptions.
This one-page barn plan is also from LSU AgCenter but it's for a 30 X 24 barn.
In the PDF are details including the location and size for box stalls, a calf pen, a feed room, and cow stalls. Having it all broken down in this way makes it really easy for you to plan the layout of your barn whether you're following this exact plan or making adjustments to your own layout.
A bit different than the other barn plans in this list is this one from Ron Fritz of The Creekside Woodshop.
To see this barn from any angle, and to measure every single component of it, requires the free SketchUp program. Once loaded into SketchUp, you can even make large or minute changes to it and see the effects in real-time.
Once downloaded and opened in SketchUp, the barn is 24 X 26 by default.
North Dakota State University has several free barn plans. This specific one explains a 16 X 30 barn with two stories.
The plan is a single page that's a bit cluttered, but if you zoom up as far as you can, you can see the areas for things like the cow pen, feed room, and horse stalls.
This is another direct link to a PDF for a free barn plan from Tools for Survival.
This barn is 40 X 44 and has side sheds built-in to it. All of the dimensions and perspectives of the barn can be seen in the plan.
Tools for Survival has this free barn plan as well, which is for an 18 X 30 barn.
Similar to these other ones, you can zoom closer to the drawings to see the double horse stalls, cow stalls, feed room, feed alley, calf pen, and other areas.
6 Free Barn Plans
Free DIY Woodworking Plans For Building a Barn
These free barn plans will give you free blueprints and layouts so you can build your very own barn. These barns range from the simple and the small to the large and complex so there should be a plan here for you skill set and needs.
You'll find free barn plans for both one- and two-story barns here in a variety of sizes from 16x30 all the way up to 40x44. Some of the plans also include guidance on how to add lean-to's, cow stalls, feeding rooms, calf pens, and horse stalls to your barn plan.
Most of these barn plans will download as a PDF file. If you don't have one already, there are several free PDF readers that will let you open these types of files.
There are plenty more free woodworking plans that I've handpicked that you may like as well, such as free plans for a home, shed, chicken coop, deck, playhouse, cabin, entertainment center, workbench, swing set, tree house, wine rack, jewelry box, kitchen island, porch swing, bookcase, picnic table, and coffee table.