Sweet! I have some ducks who are very happy with one mate and are real gentlemen with the mating. I also find the females are a little more interested than the males most times and can be really persistent with the chase. I personally feel you will be fine with the pair. Without other ducks, these two will bond and later, if you found you wanted to add more, the chances of problems from this drake will be small. Any new ones....well, it could become an issue, depending on the ratio of drake to duck with the new. I have a mixed flock of Mallards, Grand Pekins, Pekins, K Campbells and Silver Appleyards. I've seen some strange goings on....I have one little Mallard drake who thinks he's 10' tall and bullet proof. This little guy is always going after one of the Grand Pekin ducks. Yee Haw! Ride 'em little ducky! Seriously...this reminds me of the joke about the elephant and the flea. Here she is, running around the pen with this little idiot holding onto her neck, for all he's worth. Pretty soon, if I don't get there first, one of the geese will come over and pluck him off of her. Now this is some funny stuff, yes it is and no ducks or drakes were harmed in the making of this scenario, but it's still not ideal. My point, if you can't be there to ride herd on these guys all day, everyday, you don't want a squad of 'geese police', be careful of new additions and if possible separate them for a few months before adding them to your current ducks. Will this stop all of the problems? Oh heck no! They're ducks! They will find ways to 'get into trouble' and make you laugh, in more ways then you can think of. Enjoy!