Thanks, everyone, for all your advice and encouragement! I think we're going to try to keep him, at least for a few weeks. If he gets too loud or aggressive we'll have to do something, but he seems to be such a gentle fellow that it's probably worth giving it a shot.
Our whole flock is named after Downton Abbey characters. This one was formerly Lady Mary. I suppose she'll have to be Lord Grantham now!
@TheOddOneOut , I was just reading your thread about Dominiques, and it was amusing and helpful. Would you be willing to look at my Dominique girl to confirm that she is, in fact, a girl? I can try to get a good picture later when I let them out at lunch to free range. Like your Pepper, she's a lighter shade. I'm pretty sure she's a hen, but after this Australorp rooster I'm getting paranoid about my whole "guaranteed females" flock.