The forum interface won't let me upload the Rutgers report as an attachment, but send me a private message and I can provide you with a .pdf copy.
Most nearby jurisdictions are more restrictive than Fairfax County is currently. Fairfax County also allows for special zoning permits, if you want...
After reading detrick's post, I contacted my supervisor and the Fairfax County Department of Planning and Zoning. Here is part of the very thorough reply I got from Lorrie Kirst, a Deputy Zoning Administrator in that office:
"An item that would allow chickens on lots less than 2 acres in size...