Chickens like to walk around. It is better to make a chicken coop and let them roam around your back yard. You should also get at least 2 hens, 1 will be too little. Since you need 2 hens and a rooster that cage will be too small. A coop is the best solution.

The pen area is to small for much of anything the birds needs room to move and eat and peck be in grass and dirt and the sun and the roo will not mate in a pen all he will have on his mind is to get out of this enclouser