Dead Duck in Nesting Box

[Ducky07]

Hello,

I have 3 Jumbo Pekins and 2 Cayuga ducks (4 hens, 1 drake) in a 20x10 area. They have coop containing three nesting boxes connected to the run. Occasionally I let the ducks out to free range around my Pennsylvania home. We have a small man-made pond with a pump to clean it.

Around 7:30pm the other night I collected 4 eggs from the coop without any problems. Around 11am the next morning I went to water/feed them and found the one Cayuga dead in the nesting box. No external injuries, turned toward the back of the box with her head laying over her back and eyes open. She did finish laying her daily egg.

I have not noticed a change in duck behavior except for three minor things:
One Pekin hen switched from using the nesting box to the corner of the coop to lay her daily egg.
The weather recently has improved from 30s-40s to 55-70s.
I noticed that the other females have feathers missing under their wings. I thought it was because of molting but now I am unsure.

Any ideas on why my duck died? Are the other ducks at risk?

 

[silkiecuddles]

If you had several drakes, that could be the cause of the death. Was she at the bottom of the "pecking order"?

 

[Ducky07]

I only have the one Jumbo Pekin Drake. From my observations it seemed like she was closer to the top of the pecking order. These ducks are about a year old. During the hatching process I did have a weak Cayuga duckling, however as the duckling got stronger i was not able to tell them apart. They all seemed healthy in adulthood.

Here is a picture of the weak Cayuga duckling:

 

[silkiecuddles]

Are there any bite marks or bloody spots anywhere on her?

 

[silkiecuddles]

We used to have a mallard pair. When they hatched ducklings, the drake killed a lot of them when they were young. He'd corner them and bite them on the back of the head.

 

[Ducky07]

I could not find any external injuries on her. My guess was she may have ingested a poisonous substance or had a complication passing an egg. I wondered if it had anything to do with the egg because the gang loves it outside and only goes in the coop to lay.