Yes it is possible to select for broodiness. A few breeders interested in land race breeds do exactly this.
What I used to do and will do should I care for broody hens in the future is when they go broody I let them sit for around three days. This switches their egg laying cycle off. The more broody hens might go broody two or three times a year. Say it takes two weeks for their egg laying cycle to switch back on. That may give them a six week break from laying at the height of their laying season.
Does it actually work to extend their life? I don't know and I doubt anyone else does either. One would need to let quite a few generations of managed broodies live to full life span which may be 10 to 12 years. 5 generations of that is a 50 year study.
This is all very educational and interesting to me. Appreciate your responses.
This group of hens who are more disposed to broodiness seem to have a fairly predictable 5-6 weeks on lay/10 days to month off lay cycle (depending on whether or not they broke brooding and when). The last ten days of laying they display broody behaviors -- sitting longer, being mean, puffing up, etc. Then they want to sit. And so on.
It seems like they have their own built in "break" mechanism going on. And I figure if that at that rate, they are still laying around 200-240 eggs per year. Even with declines into their 2nd and 3rd seasons, this feels fine to me. Certainly paying their rent, so to speak. And if it helps them live less stressful and fuller lives, wonderful.
Plus they are doing something absolutely valuable: brooding their offspring. There's a lot of things in life I don't have, but one thing I have out here is space and nature for chickens. So if I keep more healthy hens who brood their own young and lay a reasonable amount of eggs, even from a self interested perspective, I think I'm doing pretty well.
Plus all the other benefits. Eating the grasshoppers, fertilizer for the garden and trees, etc.
(if I don't count all the poop scraping, flea killing, butt cleaning hours. That's the love part).
