I have an incubator full of 25 call duck eggs for a couple of customers, due to hatch later this week. But when i set them, I had just found a nest of 7 eggs that one of my girls was hoarding so i put those 7 in also. Apparently she had started incubating them a bit, they are definitely further along than the others, so i think i will up the humidity on them a day earlier than the rest.
Yesterday i noticed the same girl was sitting almost all day. I think she wants to accumulate another nest. So while she was off for a few minutes, I laid 2 more eggs nearby the 3 she had. Later she gathered them into the pile. So i might just let her keep these and see what happens.