thanks for posting this Alison, its amazing to see how low a "lip" is necessary to keep the chicks safely off the ledge at this age - most other boxes have much deeper wells for the nesting areas ...
That's a good thought, TPC! I'm afraid the lip on the nest box wasn't enough to keep the chicks off the ledge for long . . .
When a parent arrived with food, all three went back into the nest box
But not for long . . .