On a early hunt this year we found a field with a few hundred crows in it with a cell tower on the property line between the woods and the field they were using.  We opted to use the cell tower right-of-way to access the woods to intercept the birds.  When we came out we had a surprise on our windshield.  Not only the note on the windshield but the owner of the field was standing there.  After a brief introduction and explanation of what we were doing all was good.  He even gave us permission to hunt other farms he had.

The moral of the story is:  Do not be afraid to ask a farmer to hunt crows on his land.  They all hate crows and I'll bet your success rate will be 90% or better.