The pens

For the Cornish Cross, we are following Joel Salatin's pastured poultry model. 
This involves having the chickens out on grass in small bottomless portable pens
so they can graze yet still have protection from predators.  The pens are moved
onto fresh grass each day.  Joel estimates that the chickens can get 20% of their diet
from grass and bugs.

As we don't have that many birds, and to reduce the risk of catastrophic loss, we made
two smaller pens, each about 4' by 8'.  Here is a picture of the construction.

And a better view of the internal construction.

The base is made of treated 2x4's, and the rest of the frame from 2x4's ripped in half
to reduce weight.  It is held together with screws and waterproof glue.

There are two hinged roof doors.  Initially, one was covered with corrugated galvanized
and the other was just netting like the sides.  In the Texas sun, however, we found that
all the birds crowded into the shade of the galvanized side so later we replaced the
netting with galvanized as well.  

You can see here the netting on the sides has fairly large holes, about 2" by 3".  Later,
thinking about raccoon paws we went back and put poultry netting over the sides.