Would sub-sonic cartridges make less noise?
Do you have any experience of them, and do they kill cleanly?
Sub-sonic shells will reduce the noise significantly, but at only two thirds the velocity of normal cartridges will also be less effective.
It’s not so much the hitting power – most shells have plenty to spare – but the fact that your lead pictures will be completely different, because they are so slow.
Like you, I have many fields that border houses or villages and find that I can minimise disturbance by using the wind to mask the sound of my shots, i.e don’t fire directly downwind towards houses.