CricketR4, don't put the duck eggs in until the chicken eggs are done. Two reasons: One, if the chicken eggs are dead, then they are full of bacteria that could infect your duck eggs. Two, hatching is messy. If they hatch successfully they will do so in an incubator full of early-stage duck embryos, spreading goo, moisture, ick, and bacteria all over them and knocking them all to heck in the process.
With a little practice, you can easily tell whether they are still viable. Try waiting until after dark, and using a super bright (LED is great) flashlight to candle them. You want to see a bright area about 1/3 the size of the egg (or a little less), and the rest mostly dark. If you watch long enough, you should see independent movement around the edge between bright and dark (i.e., not just sloshing). If you see that the whole thing is bright, then you've got eggs that never developed. If there is no movement, you may or may not have viable eggs--they might just be sleeping. Try again later. If everything sorta sloshes around, then you've got dead embryos or babies. If it's all dark with only a tiny bit of bright, you've got either a dead baby or one that won't hatch successfully because there's not enough space in the air cell. Compare your candling to the many pics online of late-stage candling.
Or, you can just wait a week and see what happens.
Odds are, with that many under her and the weather like it is, they're unlikely to have developed far. On the other hand, cold eggs does not mean dead eggs--my broody hatched a batch of three (out of three) eggs this past January. At one point she was up getting exercise and I reached in and found her eggs cold. Scared me. But she went back to them, and they were fine. Still, if she can't cover them all adequately, then none of them end up developing usually.
Good luck! Let us know how it progresses.
We're going to incubate the duck eggs though, so hopefully we'll still get babies.
