I rescued 4 chickens (2 Isa browns, and 2 Easter Eggers, 10 month old) from an abusive situation last December. They had been kept in a 2 x 4 cage with a wire mesh bottom, fed only scratch grains, water dish was filthy and cage was disgusting and stinky, and, of course, not laying eggs. They...
My Cinnamon Queen just laid for the first time yesterday (20 weeks old), and I found one hard-shelled egg in the coop, and two softer shelled eggs, with a soft spot on each, in the henhouse. 100% positive this all happened in one day. So yes, it's possible. Yours seem to all have good shells...