I have a Pekin female duck. And a Rouen female duck. I assume it is female because I got them as chicks at the end of April and it is now mid September and it looks like a female. Yesterday, the Rouen mounted the Pekin, biting the neck, holding her down, and initiating what looked like mating. Now, I am confused. There is not a curly tail feather... there is not ANY green on head. She looks just like a female Rouen. Here is a pic of her just last week. Any advice?