That could explain their appearance in Link's Awakening. You can get a picture taken of Link running looking panicked from a chain chomp. I think there was one as someone's pet too, though I can't remember for sure. It's been a long time.
Yeah, once an element appears in a Zelda game they like to bring it back now and again for fans. Hmm... I think you're right, I do recall there being one in someone's yard but I forget where.