I use 2 PVC feeders in my run. Straight down 3ft with a Y connector on the bottom so it gravity feeds as they eat out of the bottom opening. I have found (3-4x) an entire tube emptied around the bottom of the feeder all over the ground. I cannot figure out how they are doing this. They would have to pull off the bottom until the entire tube is empty. Any ideas how or what is doing this???