Hello,
First, sorry you are going through this. It is really tough!
You can get Tylan 50 at the feed store, no need to go to the vet. Be sure to ask at the feed store for needles and syringes. Ask for small ones and tiny needle. Some people give this medication orally, but it's really meant to be given as a shot into the muscle. This medication is not necessarily meant for poultry but it does work. The dose I have seen many times on here is 0.5 cc (or ml is the same thing) for large fowl, and 0.25 cc for bantam Find the meatiest part on the chicken breast and inject there after pulling back on plunger to make sure there is no blood) It can save your bird, but it may become a carrier of this respirtory illness. It's a difficult situation honestly, and there is much controversy regarding it. You can go ahead and treat her while you consider all the implications. Good luck!
Stacy
Oopr, realized you are in Canada and not sure if your feed store will have it or not. Sorry!