I also have a Springer that did the same thing in his early training. Hehas now been hunting for 5 years.
I used a check cord about 20 feet long. I began by putting the pheasant wingfew steps away. Once he retrived it, I gently pulled on the leash
and used my "Drop it" command into my hands. He was then rewarded each time he did it successsfully.

I then increased the distance while still on the leash. Soon he was retrieving from the total distance and dropping the wing
without any command.Eventually, he retrieved and dropped the bird to hand without and cord.

At that pointI thought all was well and good until we hit the field for the first time.
When that first bird dropped from the sky, he went directly to the bird, covered it and looked at me like I had two heads.
I called him over, told him to drop it into my hands which he did reluctantly.
I then picked up the bird and gave it to him. He was full of excitement. After a few moments, I called him over and told him to drop it
into my outreached hands, whiich he did. He was then rewarded not only by a treat but also by kind words.

It did not take long before he retrieved the birds, came back to me and dropped it into my hands.
He now lives for the praise he receives when he does good. He can hardly wait to get back to hunting after he releases each bird.

I understand many folks have their personal way of teaching Force Fetch their ownwaybut the way described above worked well for us both.
He now understands exactly what is expected and lives to be afield.
Good Luck!