A good strain of CLB will lay very well. I can put you in touch with someone who had a nice little flock from my birds. Black Coppers can be tricky to get to lay well, but I kept my best layers and I had started crossing my high laying dark egg cuckoo strain back in to give a very smart looking black bird. Someone contacted me the other day to say how well all the birds she had from me had layed, and what lovely eggs they were. Also you can cross the leg bars and marines to get green egg layers.
I can't remember who had my lovely Black Copper Flock, but it was someone in north wales, and I know another guy who had the last of my Cuckoo Maran breeding flock which he is very pleased with
In my experience the araucana eggs were small, but I did a quite successful cross which again laid better eggs and more of them - though not more than one a day
[size=78%]. [/size]You can also cross a double gene blue egg cockerel (not many around) onto a sussex or commercial white egg layer to get larger blue eggs and more of them, though not as good colour as pure CLB
The supermarket ones are generally from Cotswold legbar hybrid birds readily available but quite expensive, but the colour is often pretty poor more of a murky greenish hue