I've never tried it myself, nor known anyone who tried it, but I have *heard* that women in developing countries often hatch eggs by carrying them around near and/or under their breasts. I guess the humidity near the body must be pretty close to what a broody hen would provide... and the temp must be about right too.
Of course, you might end up breaking one... certainly riskier than an incubator... but I would love to hear how it goes if you try it.
And don't feel too badly about those chicks. Even under a broody hen not all the eggs will hatch. Chickens are "prey" animals, and as such, their survival strategy is to produce many more offspring than are expected to survive to adulthood. Nature is cruel sometimes. At least you tried.
And let us know if you try the "bra" technique (I don't think it was a joke--I think the poster was completely serious--and if they weren't, then *I* am). I'm curious how it would work out.