They do sit on top of the hen, particularly at a new nest site. Given your hen isn't laying yet, she won't have an established nest site. All the roosters here will sit on top of their hens when they lay at insecure sites or often new sites. I did provide a link which had a picture of a rooster standing over a hen. I have many more pictures of roosters siting on hens but it's a bit difficult to see exactly what's going on because they're in long grass, or under bushes. It's what a good rooster is supposed to do. Many people who study their flock and particularly those who free range will tell you the same. This behavior has been passed down through generations from the jungle fowl and despite what some will say about the domestication of chickens erasing such behavior it has been proven over and over to be wrong.
