Most large towns have a company which specializes in chains, sprockets, etc. I live near a small town an there is one (Merly Chains, Milton Ontario). Chains are almost always standard. Yours is probably an english or metric size, not a kubota special. It costs a lot to make a custom pitch chain and there is no reason to do so.
Look online or yellow pages for chains power transmission, or something like that and you'll almost certainly find a place nearby. A lot of these places makes their living off small sales, so they should be happy to sell to you. Bring them the chain and they'll almost certainly be able to replace it. for not too much money.
Failing that, McMaster Carr and like places probably have it but you'd have to wait and pay shipping. Unfortunately, they won't sell to Canadians.
Chain can 'just break' if you hit a rock or something, but there is often an underlying problem like misalignment or worn sprockets, too much slack, or some such. Have a look around, and don't be surprised if you have to fix something else.
