They are all continuing to do well. Feathering in is progressing rapidly. Once again, today they remained crouched in the nest but with no sign of trying to exit the nest. Today I watched them from below--occasionally one would hang its head over the side of the nest.
Robins leave the nest at thirteen days old. I'll continue with daily photos as long as I feel that I'm not disturbing them too greatly. My daily sessions last for only a minute or so and only once per day.