I am very sorry for your loss and the pain you are feeling. Your sweet duck knew you loved him. Due to my personal religious beliefs, i fully truly believe i will see my beloved fur & feather babies again. But i wont say any more on that subject since religious views may not be shared, other than to say again, that at the Least your duck knew that here on earth you loved him very much. Re improving your coup security, before i ever got chickens, i researched thoroughly on backyard chickens forum how to secure my sweet girls (and boys), against the many predators that lurk in the surrounding woods. All my coups AND runs consist of 10×10 chainlink dog kennel panels. Then 1/2 hardware cloth wrapped & covered on sides, top, & dug/flared 3 feet under ground. I also have 2 lgd that patrol & protect. So far nothing has ever gotten in at night. I did lose some to a sneaky fox several years ago during the Daytime in winter months, while the chickens were free-ranging. That fox hunted around the dogs. I HAve made a few tragic mistakes through the years that resulted in deaths, & the truth is i Do often still think of those sweet girls with great sadness. (Sadness for ME, because i wish they were still here with me, even tho as previously stated, i fully believe that through Gods Love for ALL his creatures i will one day be re-united with them.). There is tons of priceless information re how to protect from predators on the various backyard chickens forums. Read, research, protect. And then, to honor the life of the sweet duck you lost, dare to love again. You will never forget him & the special personality that he was, & that is ok. Again, very sorry for the pain of your loss.