My personal favorite chicken farm: All glass around a bunch of chickens in a single space. Below the chickens, a hopper going down into a dispenser aimed upwards. A redstone clock on the dispensers fires the eggs. In time, the eggs will accumulate faster than it can fire.Does the old method of having a chicken farm no longer work? where you place water blocks above a group of signs for the eggs to fall through? I've tried this and the chickens drown.
Around the glass: Open space.
On chunk reload: kill all the chickens outside of the glass.
Yea, it's taking advantage of minecraft's "mobs don't stay in a pen" bug.