anyone out there have positive advise for keeping birds with coryza?

I've been on here numerous times with questions about my one rooster who is showing signs of coryza and all the advise keeps turning back to culling. I'd hate to do that...we have them in a confined coop and he's with 2 other hens and a duck...This will be day 3 of Bimethox treatment and after he's well ( hoping the meds work ) I'd like to keep everyone. I know about closed flock and no breeding which I'm fine with. I guess I'm just trying to see if anyone out there has experience and advise with this and also if it's for sure safe to eat eggs of carrier birds. My birds are special to my kids and they don't understand the 'kill them' idea which I know seems to be the best way to handle this disease. I'm also confused as to why they even make medicine that treats this if all I keep hearing is cull them.....