Ideally they should not be allowed access to the nest. Alternatively you may get some eggs crushed/broken at varying stages, and probably newly laid eggs from the other hen. In short hatch rate is likely to go down. I would mark her 8 eggs with a marker, so if they decide to share a nest you can identify the new ones. You probably don't want ducklings born 2, 3, 5, 7 days apart, which is what can happen if you can't identify the original 8. Brendasue

She's in the temporary pen INSIDE the regular coop, right? And the coop is safe from predators? Then she should be fine. If it is drafty, you might set up a couple of breeze barriers. Drafts are actually more of a chick-killer than simple cold temps are. But I have brought broodies with eggs about to hatch inside before, and the hen has never left the nest. So if you feel more comfortable bringing her in, do it. You'll know pretty much right away if she's going to settle down or not, and if it freaks her out too much, just return her to her milk crate pen. Velvet ~:>

Exactly what gardendawgie said. :) I'd add that if you leave the nest in place where it is, you need to make sure the nest box is secure and enclosed so that the newly hatched chicks cannot fall to the ground and hurt themselves, and so other adults cannot get in and harm the babies or fight over who gets to set the eggs and kill the unborn chicks. Once the hatch itself is done, then you can move mama and babies to their own enclosure. If it is possible to move the nest box itself, mama, eggs and all, to a secure pen for the little family, do that. Make sure that you have a waterer ready that the chicks cannot drown in, and appropriate food for the chicks--either chick starter or grow mash. Good luck with the hatch! :) Velvet ~:>

Congrats on your chickens! And yes, having chicks IS more exciting than eggs. :) I've got a chicken info site here that can answer a lot of your questions: http://jackshenhouse.com/ But as for broody hens, they are easy to spot: They will sit on a nest (eggs or not) for hours on end, seemingly in a trance. They will come off the nest once or twice a day to eat, drink, poop (huge, stinky!) and maybe dust bathe, then go back. They will be fluffed up and emit rapid fire 'cluck-cluck-cluck' sounds, growling/shrieking at anyone or anything that approaches them, and generally be grumpy. :) What you can do to ease your hens' worries about taking her eggs is to take a moment and praise her for it. After all, it IS a big deal. :) I do it for my girls when they are especially proud of the eggs they've laid. Sounds silly, but they do understand it and it seems to calm them. You can crack any egg into a dish and tell if it is fertile, just look for the white spot on the yolk. If it is big and has rough, undefined edges, it is called the 'blastodisc' and is NOT fertile. Fertile eggs will have a more defined, round, doughnut-like germinal disc that is now called the 'blastoderm'. Pictures and more info here, read the section called 'Fresh Egg Breakout': http://pubs.caes.uga.edu/caespubs/pubcd/b1166-w.html I've done it with mine (refrigerated or fresh didn't matter), it worked even without letting the egg sit as brendan said. I just cracked mine into a small dish. Also as brendan said, breed differences don't matter--if your roo can make the climb, love will find a way. :) Velvet ~:>