SpicyDisaster
Songster
OP stated they were unaware and are newbies at this. We all make better decisions with experience in any subject.Not being negative, but why did you bring a sick rooster into your flock? The old saying "An ounce of prevention is worth a pound of cure." certainly applies here. Hopefully, you'll learn from this experience.
Echoing what's been said above, check into necropsy before culling to know what you are dealing with and if it's something the rest of your flock will be carriers of for life.