The third Chrome Dimension level can be unlocked from a chrome ‘egg’ found in Level 1-20. The egg in this one is slightly high up. I did not zoom out in the video, but you should zoom out to get a better view of the egg. The Chrome Control guide will have more information on zooming out.
The first bird should be used to take off most of the right side of the structure (all but one pig). The second bird should take out the remaining one pig.