Putting a chicken down?

So after a lot of work feeding her, and some improvement (yesterday she looked really good, walking around), today I find she has taken a turn for the worst and seems pretty much paralyzed. I am pretty sure it is Marek's now, and not botulism. I think it is time to put her down. Nobody in my family has the heart to do it, so I am wondering who can I go to, to do it humanely and inexpensively? Also, I have seen in other posts about conducting tests to determine what the cause of death was? Where /what types of places can I get that done? And how much is it to get done? (If it helps, I live in Vancouver, BC)

I take my parrot to an avian vet, but it is really really pricey for just an appointment. Is there some sort of cheaper poultry vet?

Last case scenario, if the vets are too expensive, what is a humane way we can put her down ourselves?


Thank you