If you're hunting on foot look elsewhere than field trial lines. Field trial dogs are meant to be very energetic and wide ranging.
I disagree with that for several reasons...
All I can say is I trust the breeder/field trial guy who advised me, he's been running Britts fr decades for the love of it. Last time he hunted South Dakota he had trouble keeping his dogs on his side of the section until they tired a bit. He expected that, usually he's on horseback when the dogs are working. But his dogs win. Must be a reason the breeders I looked into in the region stress their lines are bred for foot hunting.