Look at that beak! Im not tricking you here, yesterdays shot is one day old and todays shot is two days old - amazing growth in 24 hours. They wont be in the nest for very long.
It was HOT yesterday, the chicks were panting to cool themselves. Mum and Dad are bringing food in relays, and in between deliveries the chicks sleep. Sleeping conserves thier energy so they can grow faster. A system that obviously works very well!