Personally I never worry about breed, age, or if she is a first time broody. If one goes broody when I want a hen to hatch some eggs I give her eggs. I have had some better than others but I've never seen a correlation to any of those factors. I've never had one abandon a nest.
By putting...
That's what I usually do. Give some to a broody and put some in the incubator. When they hatch give them all to the hen to raise.
One time I put some eggs under a broody hen so the hatch would coincide with when my granddaughter would be visiting. I did not put any in the incubator. A...
Yes. Even if they were fertile you can still use them as long as you collect them every day. Since yours are not fertile you could go longer but I'd stick to the every day collection.
Yes, people do that all the time. A committed broody hen will hatch turkey, pheasant, or duck eggs and will...