In this picture one can see too things, firstly that most hatchlings are developing body plumage: the lighter coloured feathers which are now only slightly visible at the back of their heads. These will keep the birds warm (sole purpose of plumage).
The other thing is that one hatchling is not as developed as the others (right most head), and that the head count stops at 6. Unfortunately one hatchling has not made it and I am hoping that the 6th and youngest hatchling will not share its fate. It is so difficult to observe such things. A picture does not show much. It hurts every time when watching the live stream and seeing that the little one gets pushed around and does not manage to make its way to the top to get food. But one must remember that intervention does not solve anything. On the bright side though it did manage to get a huge spider last night and I was so happy to see the little featherless head this morning!