Can anyone tell me what day and why this duck embryo stopped developing?

[gabby4-Hagent]

I am a 4-H agent, and a parent brought me 12 eggs from her Pekin ducks. Only one of them survived past day 14, and I did not candle any more after that. This was her ducks' first time laying eggs, if that matters. I attached a photo of the embryo. After 32 days, it did not hatch, and we candled and saw no movement, then water candled and got no movement, and it sank. I will post the photo, but it is bloody. I inherited around 20 incubators that are the farm inovators circulating air ones, so any recommendations for better incubators would be great! Would love insight as to why all the other eggs could have stopped developing and all got the ring of death. (they where all very poopy and muddy when she brought them in).

 

[Egg Snatcher]

Looks like maybe day 24-27