I would suggest that in the future when you open a new box of broth you write on the top what day you opened it and what day it needs to be used by. There's usually a note on the packaging about how long the broth lasts refrigerated after opening, which is generally 7-14 days.

I am guessing they are opened (otherwise why are they in refrigerator) - dump 'em after that long for sure.

I generally keep for about two weeks, but won't use unless I boil it.

I'm revising my answer. I wouldn't use an opened box past 1 week, and I agree with SueonFood that you should boil it after 4 days.

Amy,
You didn't say if they were open. I'm guessing they are. DON'T use them. I wouldn't keep open boxed chicken stock more than 4 days, if THAT, without boiling it. You can always freeze the extras in ice cube trays or small containers. If they're not open, you should be fine.

They've been opened right? I wouldn't use them after 2 weeks.