Well, when light hits something, most of the wavelengths are absorbed my the object. What we see are those that aren't absorbed, but rather reflected. Chicken abosorbs those that make up the colour green and instead reflect those that are interpreted by your eyes as a rather beige colour.
If you want it green then paint it.=)
By the way, you can find black colored chicken in Japan. It's true.
Check the link below.
You want to take a look at it after the left-over barbecue chicken drumsticks have been stuck in my fridge for three weeks.
Best wishes - Majikthise.
because it wud b rotten.
because they're blue
Because it isn't.