Need help with chicken spacing

[MATTATTACKED]

I am looking to build 2 chicken tractors. They don't necessarily need wheels or anything but just the look of tractor. I need to build them large enough for 8 chickens each but as i am new to chickens I don't want to cramp them. They all will be Araucana chickens (8 blacks, 8 Golden DW).
Note. I would like the actual run area of the tractor to be big enough that I do not need to let them out. These are going to be my show chickens and I don't really want them being involved with my other chickens.

This is to kind of the design i'm looking to build.

http://www.google.com/imgres?imgurl=http://1.bp.blogspot.com/-X71KT3WG0U4/UUet8a0dvwI/AAAAAAAAABs/trBoPuafx94/s1600/ChickenTractor2.jpg&imgrefurl=http://sustainascapesbham.blogspot.com/2013/03/normal.html&h=480&w=640&sz=76&tbnid=LXFCZqfRbROk1M:&tbnh=92&tbnw=122&zoom=1&usg=__Rk4IqW54pC3W5prxR2wRN5x0dsQ=&docid=bEdRxlc2qHDDxM&hl=en&sa=X&ei=vlV0Uc3lOI7e8wSui4DYDg&ved=0CGcQ9QEwAQ&dur=443


Thank you so much for all the help everybody! Any information will be greatly appreciated.

 

[Judy]

You could go by the "minimum standard" that is often quoted on here, of 4 sq ft per chicken in the coop and 10 sq ft per chicken in the run. That is big enough that you will hopefully not have overcrowding problems. Here's a post about space by an experienced chicken keeper that I like to share:

https://www.backyardchickens.com/t/700308/coop-and-run-size/0_20#post_9504811

If you're looking for design or planning help, there are a lot of tractors similar to that one in our coops tab (top of page) under tractors. It would be simple enough to omit the wheels.