How to build a chicken tractor

Lots of people let their chickens free range around the barnyard during the day. Sometimes the varmints get them, so enclosing them inside a chicken tractor would keep them safer.

Chicken tractors are basically small coops without a floor. Some have wheels, some don't. The units are moved often so chickens always have access to fresh grass and bugs. And the birds leave natural fertilizer behind.

Rich McGinnis is the co-owner of a website called DIYchickencoops.com. He says a chicken tractor is easy to build, but you need to size it correctly.

• READ MORE: 7 Characteristics of a great chicken coop

"It really depends on the size of the breed, but kind of the rule of thumb is somewhere between 3-5 square feet per bird," says McGinnis. "And what you don't want to do is you don't want to over-crowd your chickens, so if you want to err on the larger side, that gives them a little more space, and it also allows you to add hens later if you decide that you want more eggs."

The tractor coops can be made out of scraps from other projects. If you purchase the materials, McGinnis recommends kiln-dried pine, which is less expensive than other options. Wire cloth or mesh should be strong enough to keep predators out. You must also decide whether your chicken tractor will have wheels based on how many people will be moving it.

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"You'll see tractors with no wheels. So the idea there is basically that they'll have handles, and it usually requires two people to lift them and move them. You'll also see tractors have two wheels. Those tend to be more like a wheelbarrow, where you've got two wheels on one end, and a handle on the opposite, and you lift it and push it," says McGinnis. "The third version is a tractor that has four wheels. And that I think of as being more similar to a wagon."

McGinnis says a point to remember when adding wheels is to make sure they're large enough to handle the terrain.