How to build an outdoor rabbit pen...

In Spring 2008 I built the rabbits new pens with iron gates and little houses for shelter.
The rabbits are also allowed at different times to roam the rest of the yard and garden with supervision.
They even have their own herb garden full of mint and basil where they can graze
and their pens are bordered by purple lilac bushes.

You can make a pen any size, but remember these important considerations. The pen is designed more to keep predators out than to keep the rabbits in. If there in enough room and fun stuff in the pen the rabbits probably won't try to get out. It is very important for the rabbits to have access to a shaded area at all time and for them to have shelter in case of rain. Never leave a rabbit outside if the temperature is over 80 degrees. Heat is much worse for a rabbit than cold (since they have fur coats). If you are going to have the rabbits outside often, it is a good idea to give them a flea treatment (only use Revolution for cats and kittens as it is safe). My rabbits live in the house, so this is merely a play area for them where they spend a few hours on nice days. I don't recommend keeping rabbits outside full time and you should regularly check on your rabbit when it is outside. Here is the large pen I built originally for four rabbits...

I took this at night so it's easier to see the netting. See numbers on photo.

1. Be sure the gate is big enough to get the push mower through. I made the mistake of too small of gate the first time I built one of these and kicked myself.

2. Standard farm/garden fencing (36" high) with standard posts. Attached with plastic zip ties for easy removal.

3. I doubled the poles up to hold up the net supports. Secured with zip ties. Kind of ugly, but I had a bunch of posts.

4. The netting (usually called bird netting in the store) covers the top and all the sides with holes only over the gates so you can walk in. This keeps hawks and other predators out. 

5. I used electric fence wire around the outside edges and radiating out from the tree to support the top and sides of the net. Net is secured in many places with small zip ties.

6. I have small movable piece of fence on the inside. I use it "shrink" the size of the pen when I need to catch the buns to bring them in for the night. I also can use it to keep them away from any holes they might try to dig under the fence (the buns I have now don't dig though).

7. Tree in the middle for shade is very important to a happy bun. You never want the bun to be where it can't get out of the sun at any time of the day.

8. Dog house with some hay inside in case it rains.

9. Change the water dish everyday as lots of bugs and other nasty stuff can get in.

Make the net high enough so you can walk into the pen standing up (it's hard to catch a rabbit while bent over) and to account for some net sag over the winter. If the net sags, just add more zip ties and tighten the wire. Notice the bird netting drapes over the sides and is attached to the fence. This keeps out cats and other nasty critters.
The clothes line pole just happens to be in the pen, it is irrelevant to the pen itself. Note that the tree and bushes provide shade for half the pen at all times during the day. Before you build your pen, watch where the sun hits the ground throughout the day and then choose the best spot for shade. Also be sure that grass in the pen isn't treated with fertilizer or chemicals. The buns will eat lots of grass and weeds!
Here are the buns enjoying their pen. In this shot I have the pen split in two because the rabbits were fighting when I first adopted Hop and Flop. This was before I put the bird net up.
Another photo of the pen decorated with hanging flower baskets! This was before I put the bird net up.
I planted some fancy lettuce in a window box and when it was ready I moved the box into the rabbit pen. Here is Chatfield in the pen getting ready to select from his gourmet lettuces.