An egg usually spawns near most chicken coops, including three respawn points at the farm north of Lumbridge, at Fred the Farmer's chicken coop, two respawn points at the farm north of Port Sarim, at the chicken coop north-east in Entrana, and in front of the Chicken Shrine outside the Evil Chicken's Lair in Zanaris.
If you use an egg on the Chicken Shrine it will say in your chatbox "Nice idea, but nothing interesting happens".
Chickens can lay eggs. When doing so, squawk! will appear above them. The egg laying is related to a tick cycle that is off by default. Therefore, when a player poisons a chicken its tick cycle will be turned on resulting in not only the chicken receiving poison damage but also making the chicken lay eggs every once in a while.
Monster Combat level Quantity Rarity Imp 8 1 Uncommon