This is in the first level, "Scrambled Eggs", of the second hub world, "Veggie Village".
Right after talking to Tess at the start and crossing the bridge forward, to the right is a farmer on a stump and to the right of that is a barn, a pen, and 8 chickens. You have to do this to get the "U" in "LUCKY" anyway.
2 chickens are around the pen, 1 behind the boxes to the right of the barn, 1 on the top roof of barn, 1 on the side roof of barn, 1 in the gated room on the left side of barn (which you open by melee-ing the brown/white wind switch, and 2 to the right running from bush to bush.