There isn't a harness or leash marketed for quail, as typically they are poultry or game birds. You could test out an aviary harness for parrots, but it may not support your quail's body shape/size adequately.
Try the stop-start method. A dog pulls because they feel it gets them where they want to go more quickly. When the dog pulls, stop. Only start moving forward again...
The use of harnesses is controversial. However, when used correctly, a harness provides a great way to get your guinea pig some fresh air. Choose an 'H' shaped harness that...
If you don't want to kill them, you could gather a couple friends and have them all hold butterfly nets. This way, you can have you and your friends surround...
First, catch your quail. Then fold it with a rag, so only its back is showing. Then grab a wing (still holding the quail, and gently snip a centimeter or...
Paralysis, and prolonged exposure (especially to the neck or heart) can kill. You could incapacitate someone, but if not careful, could outright kill or permanently paralyze.