I have seen a Great Blue Heron every day this last week investigating the coop and watching the flock free-range. He is such a big bird and it is very alarming to the girls, who run for cover immediately. I would assume that only small chicks would really be in danger, but does anyone know about Herons (and what the largest size animal they would attack is)? My free-rangers are now 16 weeks & up to adults and I have 3 roos to hopefully sound the alarm to my dog (who loves to chase the Herons, luckily). It's just a bit disconcerting watching him circle and land 15 feet away onto the roof of the house and PEER at everyone.