I went out this mornong to let the chickens out and noticed in my duck pen one of my girls is missing. They cant fly as wing clipped. Only trace of her is a few feathers on the ground. She is about 4 lbs. a khaki campbell. we have 6 foot privacy fench all around the back yard, and no trace. What could have gotten her left no trace and got her out of the yard with no trace?