not tough enough

We got a dog bed for doggie. Knowing his propensity for chewing, we went with one from K-9 Ballistics. I put it in the crate for him. Doggie wrestled that bed as if were another dog. The first thing that went was the K-9 Ballistics logo. And within an hour, he had chewed the teeth off the zipper and was into the stuffing. So I took it out and sewed the top to the bottom every 2 inches or so, covering the zipper. He broke those threads in no time flat. So I took it out again, this time I sewed the top to the bottom, all the way across that side, in three separate thread segments. That lasted about a day, whereupon he broke through one segment and was sufficiently satisfied with that since it was enough to let him pull all of the stuffing out of the bed. When I have time, I will sew it up again. This time I will put in two rows of threading and again in three segments. Eventually, we might try a Dura-Bull bed. Right now, I am determined to get some use out of the $80+ investment. In fact, when he stops chewing (I'm assuming he will), I will replace the zipper.