Unless the farm is completely isolated with nothing else around , within a radius of about 2 miles , Your best option in my opinion would be to use an Air Rifle. The .22lr bullet can travel for a distance of over a mile if shot up in the air , and if the target was missed , who knows where the bullet would end up. Another problem with the .22lr is they tend to ricochet a lot , and can be dangerous
Why not put a dead rabbit in a trap , and you never know , you may even catch a few crows as well.
John