Let me try to answer you in order Latt...
Q. Do Canadian seeds differ in any way verses US seeds. IE, seed size, germination % rates etc.
I haven't seen any difference in the seed itself I've gotten seed from four different states and Canada. It all looks the same because it comes from the same species of plant. As for germination/viability rates, I've had very good results with the seed I use. Last year the viability test was about 98%. I think this is a product of where the seed originates more than what part of North America it comes from. I had a very pleasant phone call today from someone who tried my seed last fall and compared it with several others from the area. He advised mine did very well in comparison and was in fact much more economical for him. He advises he wants about 25# this fall.
Q. Does Canadian seed get treated with chemicals differently or handled differently.
They have the ability to treat seed with fungicides in Canada that we cannot use here. The primary fungicide they use that we can't right now is Senator. They sometimes treat the seed with this before planting. The other is Quadris. They normally spray the beds with Quadris as soon as they plant before they straw. But, the stuff I get is normally just bleached out of the stratification boxes to pass inspection at the border.
Q. I would like to try some Canadian seed.
I know where you can get some this fall
Q. Does Canadian seed come up later in the spring possibly verses US seed? If so does it matter?
If memory serves, New York and Michigan seed somes up first, then West Virginia, then Wisconsin and then ours from here in Ohio. The stuff from Canada comes up about the same time as ours.
This is the only seed I've used in the past six or seven years. I'm very happy with the results I get, the quality of the product, and people with whom I deal.