One hammer at a time. If its a dove shoot you have time to cock'em both before the bird arrives. For quail, I cock both hammers at the point and point the gun up in the air.

I cannot even imagine breaking the gun open and trying not to drop the shells out while walking in on a point and trying to keep the muzzles in a safe direction. If a wild bird gets up I cock one hammer and shoot; if the other barrel is required, I try to cock it and get off a second shot.

I dislike having to thumb the hammer and lower it if I don't get off the shot. Its ok while on a dove stand or in a duck blind, but it seems risky to me while walking around in thick cover. A hammergun is just an affectation for me...Geo