There are a few key ways to tell the difference between a peacock and peahen. The first way is by looking at their plumage. The peacock has much more colorful and vibrant feathers than the peahen. The peacock also has a train of feathers that extends from its backside, while the peahen does not. Another way to tell the difference between these two birds is by their size. Peacocks are much larger than peahens and they also have a larger beak. Finally, you can tell the difference between a peacock and peahen by their call. Peacocks make a loud, screeching call, while peahens make a softer cooing sound.