I have had drakes for almost 9 yrs and can't say I have ever seen that behavior when my drake was doing it he was putting his head over his tail feathers not under them,.not like he was using his oil gland though because he never actually touched his body, he would go on one side and then the other, almost like I expected him to start chasing his tail but he never did. very interesting though.Well, after much observation, I think I've discovered why my drake is doing what he's doing. I was watching my flock this morning after letting them out and setting out their food and water, etc.
It would seem that all the males' "equipment" would randomly pop out and then go back in, well the one drake in question was trying to catch it, making the same motions I observed earlier, but it would go back in when he would almost get it. He's in for quite a surprise if he does!
Is this a normal thing for drakes, they weren't interested in the females at all during this. They are just over 6 months old.