Mike,
I am about half an hour from Reading, so not too far from you.
This is still very unusual turkey behavior -- clearly there is something wrong, as you noted, though whether it's genetic, or dietary or illness is hard to determine.
What breed is your turkey? If they are Broad-Breasted...
That is NOT normal. Something is definitely wrong. Is he weak? He may be malnutritioned for some reason. Was he attacked in any way? What are you feeding him? Any other symptoms?