I have 2, 2 1/2 year old chickens (light Brahma and Buff Orpington), 1 15 week old pullet (blue Wyandotte) and we just added a 9 week old pullet (golden Wyandotte) last week (replacing one that we got with the 15 week old one that didn't make it - not from respiratory issue). I quarantined the newest pullet as usual, but one day after we got her, she came down with some sort of upper respiratory issue (sneezing, wheezing, small amount of odorless, clear nasal discharge). I have treated her with Tylan 50 soluble for 3 days and she is good as new (yay!). But I realize she is now a carrier of whatever that was. How long would you continue to quarantine her? I planned on 4 weeks initially, but now thinking longer may be necessary. Or does it matter since she is a carrier and will always spread it to the rest of the flock? Culling is not an option; we are not selling eggs or chickens, 4 chickens is our limit, and do this for a hobby and the enjoyment of the birds.