On our last run we put bird netting over the top and it worked fine. However where we live now we get a lot of ice storms and I have had bird netting come down around our garden. So I don't want to keep repairing the netting after storms. With that in mind has anyone ever taken nylon twine and string it every 4" across the top to keep hawks out? Can they get thru a 4" gap? Or is this a dumb idea?