I never recommended 'do nothing' I stated I choose to do nothing! I shall expand on this. There is a possibility they'll contract a secondary infection but this doesn't mean they will. Its the secondary infection that does the damage and not the y/b/s in itself. If a secondary infection does take hold I'll deal with this when the time comes but until that time no antibiotics will be given. NB the use of the word 'secondary', if y/b/s opened the door up for a specific infection to each and all it wouldn't be called a secondary infection it would be called by its correct name. It so happens one loft could get e-coli whilst another loft could go down with a respiratory infection another cocci and yet another not have any secondary infection at all .........and here lays the biggest problem. Fancier A treats with an antibiotic that clears up the e-coli and tells fancier B what he treated with and it cleared the problem up in no time, fancier B believing that's the stuff he's going to treat he's birds with but finds it doesn't help he's pigeons one jot. Each individual loft has to be treated different and how you deal with it will either make or break your team. More damage can be done by administering the wrong antibiotic as it kills good bugs too leaving the initial infection less to fight against and as a result get stronger and stronger until the pigeon drops of the perch. And this is why I chose to do nothing.