Its probably a partially formed, dead embryo. I would leave it be and let nature take its course because it could still be alive for all I know. Why did you take it from the father?

Mother knows best in this rare case. Yes, just leave it a while longer.

There's an egg that some pigeons have been incubating for about 16 days now. The mother has rejected it but the father keeps sitting on it. I picked it up to candle up and I heard a watery sound from inside the egg. When I candled it, I could see the insides shifting when I tilted it. Should I dispose of it and what's happened to it?