You should make duck scarves or wigs! To protect there necks! Maybe you could do something that looped round the back of there beak like a horse bridle! I don't know ti would work or not or even be safe, it would have to be breakaway, and would take some designing, but if you could get it to hang down form the top of the head it would work, if it sat on the bottom of the neck, it seems like it would just fall down. Here are some images!
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I can kinda see it being the same idea as the horse halter in the picture! I drew it for you, sorry the words are blurry but its supposed to say, that the purple in the picture is supposed to be velcro. The one not he chest is to velcro the loose ends of the "scarf" that can hang down form he halter together to keep it around the neck. The velcro by the top of the head is a breakaway to make sure it falls off if it gets caught! I honestly don't know if its safe and sellable, but thought I'de share my idea! Tell me what you think!