Hey Jim, flies are relished by chams. If you can find someone that sells blue bottle flies those are an even better option than the reg houseflies. BB's have a larger body so if youve got panthers or veileds those would be a more approp sized feeder. (You'd be able to feed fewer)
I dont know where in Canada to get them though. I get all my flies from Mantisplace.com I dont know if they ship to Canada. Great thing about flies is you can order them in winter weather and they wont die in transit like other feeders. They just go dormant til they are allowed to warm up again. If you need food for your flies Mantisplace sells pre-mixed food and rearing containers and bedding also. So if you cant get any of those supplies from your fly source Im sure they could prob ship that stuff over the border.