SFH Cockerel sneezing and mucus on nostrils

[Mo'sMenagerie]

I have a swedish flower hen cockerel, about 7months old, who over the last couple weeks I've noticed sneezing occasionally. Today I saw that he had mucus covering his nostrils causing him to breathe heavily. I cleaned it off, rubbed some VetRX on his nostrils and put a drop down his throat. Seemed to help. He has been getting a little bit ostracized lately by the flock, too. I was thinking this was the result of his incessantly rough mating of the hens, but now I'm thinking it could also be because he's sick? He's been eating and drinking normally, and still crowing like the dickens

Any thoughts from my BYCrs about whether I should separate him from the flock now or just keep an eye on him? They are in a coop with LOTS of ventilation (a woods style open air coop) and the free range all day. They get fermented feed in the morning and then eat a high quality organic feed form a treadle feeder the rest of the day. None of the others are showing any signs of illness.

Thanks for thoughts!