Chicken tractor

I am planning on raising some birds for meat next year..But being a half acre..I don't want a year round permanent structure..I want something I can move around..allowing the birds to be on fresh ground every week..so I am considering a Chicken Tractor...simply put..it is a box covered with chicken wire with a roof or covering at one end to let them get out of the weather..I found a great website with some design ideas!
http://home.centurytel.net/thecitychicken/tractors.html

The one above is along the lines I am thinking..but with small wheels on one end and handles on the other for easy movability.

Some of these are quite small..and some quite elaborate..allowing eveyone from urban homesteaders to country folks to raise 3 to 20 birds.

From Artistic...

To plain and serviceable...

To Bare Bones Basic! The above website has DOZENS..It's very inspiring! I can already hear my husbands *sigh* of resignation!

Cheers!