In Canada election staff are paid, and seems to be mostly retirees and stay-at-home parents who staff the polls, as anybody who actually needs the money doesn't want such a short-term low-paid job.
Furthermore, in Canada (Federal), deputy returning officers are chosen by the party or candidate received the most votes in the last election and poll clerk's are chosen by the party or candidate that came in second in the last election.
In practice though, a lot of folks are hired afterwards through the nonpartisan process.
