Chicken and eggs

I am need of enlightenment (among other things!)

Can someone please explain to me the relevance of eggs for Easter?  Or chickens?  Or rabbits for that matter?  Or even bilbies?  Does it have something to do with the circle of life?  Unbounded breeding (rabbit link - work with me)?  Or is it all just a clever marketing ploy schemed in the consumerist 1980s to get us to part with more money by buying chocolate eggs, rabbits and chickens in the guise of celebrating Easter?

Either way, I do love the taste of Easter chocolate.  Psychological maybe but I reckon it tastes better when shaped into an egg filled with smarties. Or a gold-tin-foil wrapped bunny complete with red bow and bell...

Okay....so IMAGINE a bunny with a head...and a red bow and a bell....!

Or even a line of chickens looking quite two dimensional and side-show-shooting-game-like...

So much for sugar-free!