We have had chickens since year ago April. We lost a few as we learned. First to a cat after it just flew out of our pen one evening (been thinking about bird net - too late. Second to a hawk (we had been free ranging when we were home, but realize now that we have to be outside with them in sight). Third one about a month ago to two coons who worked together by one tearing through the bird net on top the run and scareing one our faverolles bantams into a corner while another coon pulled her through the the chain link run (not a sight you want to see). Tonight I just finished putting two electric fence wires on the run (one about 5 inches high above the top pipe on the chain link walls and one extending out horizontally about 5 inches from the same point. Sure is nice to see that green LED on the fencer blinking away... Chickens have a couple more nights being locked away in the coop though while I run hardware cloth around the bottom 2 feet of the chain link run, and also bury the same around the outside of the run walls to prevent digging.