Poultry Talk Ontario (pto.ca)

@Killerbunny - keeping in mind this is just my own experience with brooding guinea fowl.
By my count, today is Day 29 or so since the guinea hens started sitting on the eggs. When I went into the barn at around 5:30 to set out food for the chickens, and gather eggs, there was no guinea hen on the eggs, and no guinea hens to be located. However, at around 8:15 pm, when I went out to make sure all the chickens were in, I noticed a guinea hen sitting on the eggs. I guess it needed a break.

Here are a couple of photos taken early on. The hens started laying their eggs in the barn after unsuccessfully making a nest outside in the field. The chickens did not bother them as far as I could tell. When the hens were on the nest, there was always a male guinea in the barn with them.

You may need to do some "mothering" guinea fowl is famous for being very bad mothers.

The nest is too large for any one or two hens to cover , so possibility of all of them being a tad too cool.

As the saying goes, "...and that was that".... sort of.
By my count, this was Day 38 since the hens started sitting on the eggs.
At around 8 pm tonight, I went to the barn, shooed the hen off the nest, and candled the eggs. There was no sign of life in all 36 eggs, so I took them away. Then the hen went back onto the empty nest.
We have 3 guinea keets in the brooder, and all are doing well.
And that is the end of this young broody guinea hens "let's see how this goes" story.

@Ontario Chick - I totally agree. That is why DH put the heat lamp where he did, which was after I took the photo. It helped when there was a keet, but I don't think it helped any of the eggs on the left side.

And we must remember that these African birds have never been fully domesticated, or couldn't be domesticated. Their instincts work in a different climate.

UPDATE:
The runt of the 3 keets died a few days ago. Given that hatching conditions were less than perfect, we were not surprised.
Now that we moved the meat chickens out of the brooder, the 2 remaining keets were let out of their circular section and are mingling well with the RIR chicks. They even cuddle up with each other while sleeping or resting, and are in there "like dirty shirts" at the feeder.

Currently:
One of the RIR cockerels is protecting the 2 keets from the guinea fowl - it jumped on one then charged it. The keets do not go far from this little cockerel. The cockerel also jumped on a turkey, holding onto its neck for a few seconds.

Also, I was right about the disappearing guinea fowl - she is on a nest. I heard her calling out, and found where she is nesting. DH needed to cut down that huge area of tall grass, saw where the eggs are, and left the nest alone. Perhaps some of them will hatch and survive in this warm weather.

Jumping forward 5 days since the last post -
There are about 20 eggs in the nest, and I do not remember when I last saw only 4 guineas, which would mean the other one is on the nest. And the weather has gotten cooler and rainy. Those eggs will probably not hatch. It's no wander guinea owners just gather them and hatch them in an incubator.

Yes. The thing is they are adapted for deserts and huge flocks so incy is likely best for here.