The Chicken Coop located at https://www.eggs.cool/staking allows you to stake your Eggs and receive xEgg in return and then you stake it in the xEgg pool.
When users make trades on the EggSwap Exchange a 0.3% fee is charged.
0.05% of this fee is added to the Chicken Coop pool in the form of LP tokens for the relative pool.
When the rewards contract is called (minimum once per day) all the LP tokens are sold for Eggs (on EggSwap Exchange). The newly purchased Egg is then divided up proportionally between the xEgg holders in the pool, meaning their xEgg is now worth more Egg.
Currently you will not see the gained amount until you have withdrawn.
It started as 1 Egg = 1 xEgg, but just like LP tokens the price of xEgg changes over time depend on how many Egg rewards are in the pool.