Okay, there are five ducks in total, the first and last are already in place under the archway on the top shelf to the right of the mirrors. The first duck you have to place the duck that is by the table lamp. Place that duck next to the first stationary duck. One of the ducks is in the bottles near the cash register and looks like a bottle. The last duck is in the wood paneling next to the last green stool. Good Luck!
Extra credit if you know this reference.