Be sure to check out those nice broody hen articles in the Learning Center, they are quite helpful. A hen that is really "broody" will not be laying eggs (she may lay an egg the day or so she starts, but not more than that). They will continue to lay eggs pretty consistently in the amount of whatever is normal for them until they go broody. How often or how many eggs they do depends, some hens will lay everyday, some hens only a couple a week, it is up to the individual hen and her genetics... I have one silkie who pretty consistently lays 2-3 eggs in one week and then goes broody, others will lay for a month or two or more 4-5 eggs a week before they go broody...you probably want to put a couple of fake eggs in the nest and collect the real eggs and date them with a pencil and then give the newest ones back to her when she goes broody (how to store hatching eggs is discussed in the articles).