If you are going to use the playpen method it is better to put her in the cage for a few days. If you free range you can after the few days let her out during the free range with the others. The more space you have during the introduction the better it will go. Yes she will have to take her lessons from the other hens. Since she is the only one being introduced the others may pick on her a lot, that is one thing to watch out for. If there is no blood leave it go on. Every time you take her out it starts all over again when you put her back. There is another method of introducing a single bird. Take another hen and put her with the new one for a day or to for her to bond one on one. If you have a lager flock you may take a couple more and place in with her, to give the group more numbers.