If you are the party in Canada can drive the birds across the border, all that is needed isa health certificate from the Canadian side.
Birds can enter without anyother paper work.
If the intended birds must be transported via airlines from within Canada, crossing over into the US, then you will have to do the following. Obtain an import permit from USDA to import the birds you plan to get. The permit is good only for that importation, and only for the specific number of and species of birds you are getting. There are no restrictions on how much you can import, but there may be restrictions on what you can import. Generally what you want, and can get in Canada is not going to be a problem.