Found one of our ducks we have been raising dead today. I had checked on them around 3pm and all seemed well. They are around 3 months since we got them. They are practically fully feathered and pretty large. Forgive me we are new to this, the forum and the duck raising. But we moved them from the brooder we had in our sun room to the covered pen which really was a work shed with a dirt floor. I'm no handy man so we converted it to the enclosed pen for the ducks. Figured it would be easier to protect from predators. We used wire to close up anything large enough for any predators to get through. So like I had said I checked on them the first time around 9am, again at around noon, and at 3pm. They have been in their new pen for about 5 days. And I have been checking on them every few hours from around 8am- 3am since I do not sleep well. Anyway so at around 3pm when I checked all 6 were enjoying their pool and walking around. But when I returned at 6pm I peeked in and only counted 5 walking around. So I went in and found one laying there dead. I checked and could not find any injuries but the head and neck area was covered in like a slime. And when I rinsed the slime there was a couple small spots that were bloody. Not like you would see from a cut or something a raccoon or something would do. More like pin pricks or something. Really small spots. Anyway I checked the coop/pen over and over to see if I could find where anything could have gotten in and all of the wire was untouched. I'm baffled. I thought maybe a snake? But all 5 of the others still seem fine. Any help, advice, or experience with something similar would be greatly appreciated.