On April 3, 2012, AB Friends introduced Golden/Easter Eggs when it was still called AB Facebook. There were 10 eggs. Here are the locations.
Go to the main menu and click the "Shop" icon on the bottom right. Go to the Power-Ups section and then the Power-Up Pack and you'll see the egg has replaced the letter "O" in the word "Power-Up Pack"
Go to the main menu and click the "Avatar" icon near the Easter Egg level selection. The Bird-O-Matic will appear and the egg is in the top-right of the Red Bird picture.
Go to the main menu and click the "i" icon on the bottom right. The credits will appear. Scroll a bit down and you'll see the Easter Egg in place of the "O" in "Jonas Nyman."
Go to the main menu and click the "Inbox" icon on the bottom right. The Easter Egg is on the bottom-left along with the gift and The Blues.
Go to any level (such as Mighty Hoax 4-14) and click the "?" button on the bottom right. When you get the "Red" instruction there will be a Golden Egg behind the slingshot.
Go to Surf & Turf level 6 and the Egg is next to the fortress in the cave near the barrel. Use a Yellow Bird to clear the wood so one of the blocks hit the egg.
On Surf & Turf 37 there is an egg beneath the slingshot. Use the White Bird's egg to get it.
In Mighty Hoax 12, the Golden Egg is in the top right corner of the level. Zoom out to see it and use a Yellow bird to hit it.
In level 62 of Poached Eggs, the Golden Egg is located slightly to the top right of the Pigs' building. The egg has suspended in a piece of dirt and must be zoomed out to obtain. Use the White Bird's flying corpse to get it.
Go to Poached Eggs 3 and you will find the egg on top of the smiley face. Hit it to get it.
There are 10 Golden Eggs instead of 35 because Angry Birds Friends does not have that many episodes.