Instead of moving a chicken, you can swap the position of two vertically or
horizontally adjacent chickens. This is done by clicking on the two birds you
want to swap.
The two birds then exchange positions. If a chicken line is made, the line
will be removed from the board and points are awarded.
You can make one chicken swap without any new birds being added to the
board. If you make two consecutive chicken swaps, this constitutes a move
and three birds will be added to the board unless a chicken line is made.