The Angry Birds Seasons Easter Eggs Golden Egg #11 is located in Angry Birds Seasons Easter Eggs level 1-2: You can find it in the grass near the slingshot!The Golden Egg is in the patch of grass closest to the slingshot (look at the image below)
Angry Birds Seasons Easter Eggs Golden Egg #11 Walkthrough Video
Take notice that there are two parts in this video. The first explains how to locate the Golden egg and the second how to pass the level! Hope it is helpful: