Could it be this? The bruising was mentioned in the Assisted Hatching article:
Head in Wrong End of Egg
This malposition commonly results from an egg being set small end up in the turner instead of large end up, so it is very important to make sure that you are setting the eggs correctly in the turner. In this malposition, the chick is facing the wrong way in the egg. They will end up externally pipping at the wrong end of the egg, where of course there is no air cell. Just like a Facing Away From Air Cell chick, you will need allow more time before worrying that they are in need of help, and again, they usually can hatch all on their own. You can open the egg over the air cell to assess how far along absorbing is if it is seeming like the chick needs help. Make sure you're allowing plenty of time before doing this because most of the time, they get out on their own just fine with no interference needed.
With duck eggs, especially Call eggs, sometimes the duckling cannot externally pip the shell, but you will see evidence that it has tried. The shell will look like it has a bruise.
Picture by
@casportpony
In this case, you will need to very carefully open the shell over the bruise. Start by making a small hole with your screw and then widen it until you can find the beak so that the duckling can breathe.
Picture by
@casportpony
After you find the beak, apply coconut oil to any internal membrane you have exposed so that it does not dry out. Hopefully the duckling can take it from here. If not, and this will be common with Calls because of their short necks and beaks, you will need to go for the full assist. Just as with other assists, open the shell over the air cell so you can monitor absorption. In this case, you will probably also be able to see the yolk and will be able to know when that has absorbed too. Here is a picture of a backwards chick that is still absorbing. You can see the veins, the yolk, and the leftover embryonic waste.
Once everything is absorbed, you will likely need to finish hatching the duckling out because with no bottom shell to push on it won't have the leverage to get itself out. Since you can see everything absorbing, wait until it's done, and then open the egg and take the duckling out.