I've never used chukar in a recall pen before, but I'm sure it would work. All you should need in the recall pen is one hen.
The funnel should be big enough for them to comfortably enter. Whatever you think is big enough for them usually works.
How many chukar do you have or plan on getting or are putting in the pen?
Hope this helps,
Caleb Kordsmeier
CK's Gamebird Farm and Hatchery
www.freewebs.com/calebk273/