I had my chickens in their coop all winter. during the winter i got a new dog. i decided to let them out a couple weeks ago and my dog was fine with them didn't really chase them or bark. later that night she killed two chickens. i want to fence them in more but one of my chickens can fly over a 6 foot tall fence, i really don't like them all cooped up but i can't just let them out. Help.