My two, two and a half- month olds are still peeping...they do peep for quite a while. Here is general advice about bringing in new birds- I hope you find it useful.
Sometimes a hen will stop laying due to stress, such as moving things around inside the coop or moving to a new coop.There is also the possibility that she is older- I have never kept hens for too long at a time, but have read that the comb will show the age. If your hen has a bright, nice, red comb then she may be a younger hen and I would assume would start laying for you soon if her health is good.
I recommend that you dust your ones from aution for mites/lice also - now and in 7 days (if you see lice then do it again at 14 days also). I recommend poultry dust (permethrin) from the feed store. Chickens pick up mites and lice from wild birds and it is very common for them to have them- bringing in new birds it is important to get that possibility taken care of. Sometimes you cannot find mites but they or their eggs can still be there (personal experience).
Also inspect their legs and feet for raised scales (scaly leg mite) and treat this if you see it by dipping each leg daily in mineral oil or veg oil for 2 weeks. That will smother the mites.
Also inspect the poo for worms in a chicken from auction. It is a good idea to quarantine chickens for a month or so to look for respiratory disease (chickens don't get colds - they get diseases), so if you are set up to keep everyone separate for awhile, it is a good idea to do so.
Enjoy your chickens!
