(I know this is TEXAS hog hunting forum but this area is in Oklhaoma and no night hunting allowed)
We had a lease in OK last year. All your Rancher has to do is contact his local Game Warden and ask for permission, worked for us.
From the OK Wildlife Dept. site...
"Can we hunt hogs at night with firearms?
No. It is illegal to hunt hogs at night, except landowners can get a depredation permit from the State Game Warden in their county that will allow them to shoot hogs at night."
He can find his Game Warden's name and contact info here.http://www.wildlifedepartment.com/laws_regs/lawstatemap.htm