I specifically go to Sainsburys to buy my eggs because they sell Woodland trust eggs which come from hens that have been brought up amongst trees and natural surroundings.
The Woodland Trust
They cost quite a bit more than ordinary eggs but I believe you can taste the difference in the yolks.
I also used to work in the vegetable shop that used to be on union road, some of you may have been there. We used to sell natural eggs brought in from locals and we got goose eggs once, absolutely gorgeous.