It may be a little difficult to explain this in words without demonstrating it. I use this and it seems to work pretty well. Giving the command to "give" if the dog doesn't release the bird using all four fingers I pinch the upper part of the leg where the leg meets the body. In doing this the dog opens its mouth and then I take the bird. When I have the bird then I release the pressure and give praise.

If the dog doesn't have a drive to retrieve or is not retrieving to hand reliably then I would suggest learning to force break a dog to retrieve. The method I described above uses the same principal. Force breaking is little more than pain compliance. I am not an expert on the subject but basically you apply pain, not to the point of injury but just discomfort in a pressure point on the dog. then offer the force break retrieve dummy to the dog as the gets the dummy into it's mouth you release the pressure and so the dog learn that getting the dummy into it's mouth is the off switch for the pain.

If it is something you want to do with your dog be prepared to stick to it religiously and get some books to read up about it. It can be rough going for a while but eventually the dog will be retrieving machine! A lot of trainers use this for pointing breeds such as yours.

Oh and a word of caution, if using an e-collar be very careful you don't over use it or use it at the wrong time. You could ruin your dog teaching it to associate the shock with the scent of a bird or the retrieve itself!