Raptors will take on prey their same size if they are hungry enough. I worked at a nature center for 15 years; what raptors try to eat rarely surprises me anymore. LOL.
The Mongolian tribesman still hunt with Golden Eagles... and they hunt wolves! It is a truly awe-inspiring and extremely primal thing to watch. Warning: Some people may find this video disturbing. But please keep in mind that this is how these people survived in such a hellish environment. I think most BYCers understand living off of what the land happens to give you.
So just be aware that if the local prey population takes a dive, your large hens (or even rooster) may be the next meal option. Hunger is a very powerful motivator. It's always a possibility.