Well that was a complete waste of time.
I found bricks. I figured the configuration so they fitted in the nest box. I cleaned the bricks. I brought them up to the Chicken Palace. I dried them off in the sun. I put the top layer in the oven to heat them up. I constructed a cardboard cover for them. I placed it all carefully in 'Maggie's box', I covered it with pine shavings, I put pine cat litter in the lower part so the liquid poo would be absorbed.
I felt pretty pleased with myself.
Maggie took one look at it and went into the next box along.