Sorry for your loss, it did sound bad. There's a fairly good chance your chook can hatch the eggs and for that reason you should be aware that whatever killed the mother may be able to also kill the chicks.
If you've not buried the body --- or even if you have --- I strongly recommend that if at all possible you retrieve it, or even parts of it if that's all you can get --- and get it checked at a lab; some will do it for free. What use hatching new turkeys if what she had is contagious?
You may be wondering how maggots can be contagious, but it's likely the maggots were merely opportunists, a secondary symptom; I'd question how they gained such a foothold in her in the first place. Something immunologically suppressive is quite likely, going by the symptoms you describe, maggots in the rear end aren't generally known for causing black stuff to come out of an animals' mouth... That needs looking into.
What you describe sounds seriously, seriously nasty. There's also a distinct possibility your chooks are at risk. Some diseases can be carried through the eggs too and depending on what it was, the soil of your place could now be infected.
Hope this is a one off, not contagious, but I wouldn't count on it, I'd take very strong precautions if I were you and finding out what it was is a great and quite probably necessary first step as you cannot take relevant precautions if you don't know what you're up against.
Wish you and your flock all the best.
