Today I was shooting pigeons over wheat for a farmer. Plenty of birds around with a few decoying in but most flocked up in large numbers feeding in different fields.
As Archie Coats pointed out you are doing a job of vermin control for the farmer ( not on a driven pheasant day) therefore I would take both ground and tree shots so long as it was safe and that includes not hitting your decoys or equipment.
100% i will, don't let the landowner see you not shoot them.. Pest control as you said.. You don't want to loose your permission because let me tell you that somebody else will be waiting to take your place 👍