From DominionStrategy Wiki
Discard a card per empty supply pile.
Poacher is an Action card from the second edition of the base set. It is a Peddler variant, but it gets weaker late in the game by making you discard from your hand if any Supply piles have been emptied.
 Official FAQ
- You draw your one card before discarding.
- If there are no empty piles, you do not discard.
- If there is one empty pile, you discard one card; if there are two empty piles, you discard two cards, and so on.
- This includes all Supply piles, including Curses, Coppers, Poacher itself, etc.
- If you do not have enough cards to discard, just discard the rest of your hand.
 Other Rules clarifications
 In other languages
- Russian: Браконьер (pron. brakonyer)
 Secret History