As long as you don’t have a bird shy dog – no problem.
You will need two people, one to handle the dog, the other to work a cap gun. The cap gunner is going to need to be 100 yds away or so at first. When pup is chasing the birds you planted and totally focused on the chase have handler signal to cap gunner to pop a couple shots off.
The key here is the handler. You have to be confident and no matter what happens – do not acknowledge the dog’s actions when they hear the cap gun go off.
Take a walk thru the field at first w/o the dog. You’re attitude and demeanor has to be 100% the same walking with no dog as it does with the pup.
If you are worried the dog is going to act gun shy pup will read that like a book and they will be apprehensive.
For young dogs you’re confidence is thier confidence.
The other thing, and probably the more important thing to do is build confidence outside the world of birds and guns. Talk the dog for a walk in a downtown metro area with lot of scary noises and scary situations.
Again, when you are doing that make sure you are acting like this is no big deal…. confidence, confidence, confidence. The best guns dogs are the ones who have been exposed to every social situation imaginable.
I once took a setter pup to a little girl’s school dance recital. It was all about dealing with screaming kids, scary smells and bright flashing lights. It helped the pup bold up a bunch. I on the other hand had to enroll in a 12 step recovery program, which I am 1/2 the way thru the second quarter of the first step…
Good luck!