Age is a critical factor here as well. When I sold my runner ducks recently, I charge $20 per hen, but they were at the perfect age for selling and commanding that price. They were just over a year old, were laying eggs almost every day, and perfect health.
It's funny you mention that, because I was checking out craigslist for a couple of extra Pekin hens and I contacted one place that said they wanted $30 per pekin for pet quality. Lol, I just said thanks for getting back to me but that's too expensive for me.
For a common breed such as a pekin, I would probably pay $15 at the most, and that's if she is not too old.