Although medium eggs were popular on the Continent, the British still preferred larger eggs, said Tom Vesey, chairman of the British Free Range Egg Producers' Association, adding that producers tended to supply larger eggs because they yielded higher returns.
With animal welfare concerns rising up the agenda, it was time to re-evaluate, he said: "You have to make the consumer realise it would be kinder on the hen because it would be less stress on her."
Bigger eggs also tended to be more watery, while medium eggs sat better on the plate, he argued.
Compassion in World Farming agreed a move to medium eggs would significantly improve hen welfare. "Selectively breeding hens for high productivity, whether larger eggs or larger numbers of eggs, can cause a range of problems including osteoporosis, bone breakage and prolapse," it said.
If consumers demanded medium eggs, the industry would respond, said Mark Williams, chief executive of the British Egg Industry Council. But he warned against producers making a wholesale switch to medium egg production. "If the consumer wants a large egg, they're going to be disappointed if they go to a store and only find medium eggs," he said.
Vesey also called for a rethink of egg merchandising. Supermarket egg fixtures were currently dominated by "grey cardboard boxes that don't actually tell you very much", he said. "By and large, the egg category is pretty dull."
He criticised the fact the supermarkets located their egg fixtures in different locations, providing no consistency for the consumer.
A spokesman for the British Egg Information Service agreed retailers kept the egg category "tucked away" in the home baking section of their stores. Retailers were "missing out on incremental sales by marginalising their location in store," he said.