Natural Chicken Reproduction Question

Hey guys -

I've been raising layers for about 2 years now, and think I've got the hang of it.  I keep it simple with 10 golden comets that free range during the day and live in a barn stall at night.  But I'm thinking about changing things up a bit for next year, and I'm not sure I understand how this will work.  Hopefully you can help.

I'd like to get some more broody hens along with a rooster, and I'd like to set up a portable coop for them out in my pasture to follow my sheep around the field.  I'd like them to mostly forage for food, lay eggs for me, and occasionally brood to get new chicks.  But what I don't get is how I can get eggs sometimes, and other times let them brood.  Do I decide, or do they decide?  Do I just kick out the hen and steal the eggs most days, then occasionally let them stay on the eggs?  Or do they not brood once they have their spring chicks?  I feel like I've read enough that I should already know the answers, but unfortunately I don't.  Hopefully someone can help clarify.

Thanks!

@Dean M: "Do I decide, or do they decide? "

Our free-ranging chicken number is pretty high (over 100), so that has to be factored into what is written here.  My wife is pretty much "the decider"....she will see a hen sitting on eggs at the "right" time of year (late enough in the spring to minimize the worry of the hatchlings succumbing to cold) and make sure to protect her and her nest.  But this is in addition to hens that are !really! good at hiding in nooks and crannys in the outbuildings and will pop out of no where with a brood in tow.  If this happens too close to the edges of winter, they generally don't live.  A desired brood is helped along and pretty soon that clutch will become pretty independent and savvy of the farmyard on their own.  Then roosters are the first to get culled for the freezer once they get enough meat on them.  Good thing about having a lot of chickens is that they will lay at least some eggs right through the winter, probably in our case due to their living where the pigs are fed at night which keeps the lights on in the building until ~ 9 pm.  So this artificial dose of lighting may be inducing some of them to lay.

It sounds a bit as though you are saying that there are broody hens and non-broody hens.  Pretty much any hen can go broody, although some breeds have reputations for being more broody and/or having good mothering instincts.

 I have never heard of anyone deciding for the hen that she was going to be broody  Normally, I see people talking about how to break a hen's broody mood.

When you get a broody hen, you can decide to help her along, by adding eggs to her nest, rather than leaving it to her to fill it up.

Where do you plan on having your brood hens set their clutch?  Hauling them around in the portable coop with the rest of their flock does not sound like a recipe for success to me.  

Usually broody hens are given some place quiet, protected and isolated for the three weeks they will spend setting. You don't want hens fighting over the nest box when one is sitting on eggs in that nest...