There's currently a glitch in the game, when you throw darts in the mystery game, it might freez your session. Also animals you get from the mystery game will be invisible on the farm and in your giftbox. This could cause your giftbox not to open. If you grab a New Year Calf or Mongolian Foal from your feed, these will also be invisible. We suggest you hold off throwing darts untill they fix this issue. Here's an official statement from the farmville forums..
