Sorry...I'm late. Here we have Piperazine 52 powder in a 400 gram package for large roundworms. (ascaris) I see it's sold in the TSC farm stores in the east so it will likely be available in the Peavey Mart stores in the west. I imagine co op livestock/feed stores also should carry it. This is exactly what I have.
http://www.tscstores.com/PIPERAZINE-52-400G-P38474.aspx#.WW_ZooTyvIU
Here's a previous discussion on it.
https://www.backyardchickens.com/threads/piperazine-52-dosage-powder.1064956/
As far as other choices, I believe we have the same choices
@casportpony normally lists such as Valbazen, Safequard, Ivermectin etc. although they would be off label.
https://www.drugs.com/vet/safe-guard-premix-20-can.html
https://www.drugs.com/vet/valbazen-can.html
https://www.drugs.com/vet/ivermectin-liquid-for-horses-can.html
I haven't been able to get a fecal from my vet. I keep getting told that worms won't be an issue for me. (I think it's with consideration on how our winter kills everything. Maybe it's also because of my flock management?) They know I bring in stock only by egg.
To this point I've only used the piperazine. I'll be requesting a float test this fall. I'm sorry I don't have any more information about dewormers here in Canada.