re: broodies, it all depends on the hen. usually i'll give broodies eggs when they're due for lockdown, or newly hatched chicks, but i won't trust one to sit for the whole time because invariably they forget which nest was theirs, or give up all of a sudden, or, like my last flaky broody, take a look at these peeping chirping things and run away screaming never to go back near them again. LOL
fortunately my super-momma orpingbrooder took on those other chicks plus her own, and managed to cover nearly 30 chicks for the first 3 weeks, until we all went to a swap (me, momma and da bebes) and over half of them found homes.
I think that's going to become a routine for any broodies with chicks that can't stay warm on their own yet, if the chicks are for sale. they stayed much happier with momma, and I didn't have to worry about her rejecting them when i got home, or stressing unnecessarily while i was gone.
I've got a bunch of chicks due to hatch a couple days before a huge swap i'm going to, and I'm taking them with me, so this may be my best option, if i can figure out which broody will do the best job. i've got 4 now that have been broody at least 2 weeks.