Call duck infertility/ hatching problems?

[SmallFarmUSA]

I just candled the 30+ 1-week-old call eggs I had in my incubator, and only five have developed. This happened last batch also, except not as bad. After doing some eggtopsies, I'm finding half of the yolks disintegrate after cracking open(does that mean slight development before dying?), and the ones that don't have no bullseye and appear infertile.
I have three females and two drakes, although one is older and has a harder time getting around, so I suspect his breeding days are over. The fertility rate seems to be dropping as the laying season progresses, which doesn't make sense. Do I just need another drake? Or does two drakes cause fighting/competition which = infertility?
What am I missing/doing wrong? The incubator(Hovabator) is brand new, and holds temp/humidity well. I don't wash the eggs, so they are fairly dirty...Not sure if this is an incubation problem( so sorry if this post is in the wrong place).

 

[WVduckchick]

Although your incubator is brand new, do you have independently tested thermometer & hygrometers? Yolks disintegrating when opened after only a week of incubation sounds like maybe they got too hot.

tagging @Ravynscroft and @Pyxis for other thoughts...

 

[Ravynscroft]

2 drakes fighting/vying for the girls attention will cause fertility issues... they may be distracted and spending their time and energy keeping each other from breeding... I would isolate the girls with 1 drake and try again...

 

[SmallFarmUSA]

@WVduckchick Thanks for replying, with the thermometers I had I could only test the temp at the top of the incubator, but it was reading 101.1, tho I'm assuming it would be slightly cooler where the eggs are. I will turn it down a bit. Thanks!

 

[SmallFarmUSA]

@Ravynscroft Thanks for replying! I will go ahead and separate them.

 

[WVduckchick]

@WVduckchick Thanks for replying, with the thermometers I had I could only test the temp at the top of the incubator, but it was reading 101.1, tho I'm assuming it would be slightly cooler where the eggs are. I will turn it down a bit. Thanks!

do you have the model with the fan? 101.1 up high is not bad. I was just kinda guessing, since most of the infertile eggs I open don't usually bust that early on. Ravyn's suggestion sounds good to me, and maybe will give you something more to go on.

also curious, were the eggs that showed development nearby each other in the incubator, or scattered throughout? Wondering if maybe you have a cool or hot spot? Hovabators are usually pretty consistent though. Just thinking of any possibility.

 

[SmallFarmUSA]

@WVduckchick It does have the fan, yes. And the good eggs were completely at random throughout. I can't seem to find where I read it, but I had thought the yolks that fall apart is because of slight development (so maybe there's not even as much infertility as I thought), and I just read one cause of early embryo death is eggs stored too long, which could be my problem. Thanks for brainstorming with me!
One last Q: Can I just separate the old drake during the day, and put them all together again at night?

 

[Ravynscroft]

You can try the separation during the day and together at night, see if that works...

Yolks disintegrating could be from a number of reasons, age of the egg, age of the duck, nutrition (maybe she doesn't forage as much as the other), etc... this is why it is hard to determine if eggs were fertile prior to start of incubation in a lot of cases when people check... so hard to tell...

Best to crack an egg from each until you see fertility in both, then collect for incubation if you want to be certain of fertility...