Yeah, I get canadians and some of them are huge. I got some at petsmart once and they are a ripoff compared to the other ones I get. I just get a tub labeled "24 Canadian Crawlers". You know you can order worms online, too. Just do a google search and you can find some sites that sell them. I just did a seach and found this site, Buy Canadian Nightcrawlers from The Reel Thing Bait & Tackle looks pretty legit. I'd ask whoever you buy worms from if they use chemicals or dyes in their worms before ordering.. You don't want your frogs ingesting that. Obviously you don't want to buy the green ones.

Edit: This site actually looks better. http://www.knutsonlivebait.com/night_crawlers.html