Heidi, I read your post to my DH and asked what he would do. He said and I quote, "I would put them down, be sure everything they touched, including myself, was disinfected and tell who exactly sold you the sick birds and report him."
Obviously, if anyone asks you, you should tell him who sold you those birds to prevent anyone else going through what you're going through. The man should not be called a breeder, by any stretch. I re-read your original post and the entire thread. I know what I told you in my email, but considering the conditions these birds were obviously kept in, I'm not sure I would ever feel comfortable putting them into my flock, no matter how much better they get; not unless you can confirm with a vet that they have nothing contagious, a long-shot at best, I'd say. I'm so sorry. You can put off your decision a few days; no need to do anything immediately. If you do cull them, be sure you disinfect any ground they've been on as well as equipment they've touched or breathed on.
After all the effort I put into keeping my birds healthy and clean and someone mistreats them and passes himself off as a breeder....GRRRRRR....disgusting.
Even with my own birds, who have never had any respiratory illness to my knowledge, I would advise someone to quarantine them after purchase. I would not be offended in the least-it's good animal husbandry to do so.