I've got two cream legbars, one araucana, two marans (cuckoo & copper black), a pair of dorkings, a lakenvelder, a light sussex and five Orpingtons (including a huge cockerel) all in together and have no problems - even between the two cockerels.
Of those, most of the interesting egg layers came from hatching eggs from South Yeo Farm in Devon. The best dark brown eggs are from the copper black Marans and the best blue eggs from the Araucana (CLB are bigger but the colour is less intense and one has some problems with shell quality).