A few days ago, the parents alerted the attention of the chicks by chirping. Now, the chicks are aware of their parents presence simply by the sound of them landing on the nest box hole.
As well as caterpillars, slugs and other creepy crawlies, the blue tits are bringing in pieces of coconut and suet block from my bird feeder to feed the chicks.
From this video, you can see that all seven chicks look very healthy and of a similar size. The chick on the right hand side is perhaps slightly smaller than the others. The mother is feeding them coconut from my bird feeder.