I've got a good site for you to look at. http://www.henkeeping.co.uk
There is a real art to to feeding them. We've noticed that greens in their diet give the egg yolks a huge boost in colour and flavour. However too much greens and the chickens digestive system suffers, which contributes to reducing egg production.
Happy chickens make healthy, tasty eggs. Look after your hens, look after your breakfast.

We've tried ours with salad crops like purslane, which increases omega 3 in the egg