Every day since Martin left I've been searching for them. I've only had 1-2 eggs a day from the chickens, which given they are all in full lay of one each a day means they have been hiding them somewhere.
I looked everywhere in the pen, several times, to no avail.
Martin comes back, goes out there and finds them all immediately in the one place I overlooked - the small dog kennel. The grass has overgrown the front and camouflaged it nicely. Even more impressive is he carried them all back in just his two hands.
Looks like an omelette tomorrow night.