I don't believe there's anything inherently bad or harmful in popcorn itself. Although, I would think that, as with humans, the little corn bits can stick in their teeth or may be a little hard to swallow and they might "choke" or gag on a small piece! I would go the unbuttered, unsalted route if at all! Actually, mine love to bat the pieces around like balls and usually just lick the salt or flavor off!!