The movement inside the pip can be seen starting at 6:58 and 7:20. I'm not certain which hatchling is which but for the purposes of the description I'm using the prominence of the egg tooth and neck strength to ID them.
0:11 Dad enters the screen from the right side then disappears at the top of the screen to the right of the skywalk
0:38 Dad flies in with a very large fish and Mom quietly chirps her thanks to him
1:16 Mom stands up to reveal the egg and both hatchlings pop up
1:30 Mom rouses the rain off
1:38 after eating a few bites of fish Mom offers a much too large piece to the hatchlings then ends up eating it herself then eats more of the fish
2:32 the camera pans then zooms in as Mom offers a bite to the hatchlings
2:35 Dad moves in front of the camera blocking the view
2:42 the camera zooms out but Dad is still blocking the view
3:01 Dad starts pecking at the fish he delivered
3:07 the view switches the the second camera where Mom is eating fish
3:27 the camera zooms out then back in
3:49 Mom offers a huge piece of fish to D26 but pulls it back to break off a piece that D26 eats
3:57 D26 eats a very large bite
4:14 Mom offers another piece that is too big to but D26 grabs a small piece of it
4:18 the camera zooms in
4:19 D26 grabs another small bite from the large piece Mom offers
4:22 D27's head pops up
4:24 a little gray speck appears at the bottom of the pip that may be D28's egg tooth
4:30 D28 topples over
4:40 Mom gives a bite to D26 then eats a dropped bite
4:49 Mom drags the fish closer to the nest cup
4:51 Mom feeds D26 a series of quick bites while D27 gives begging calls
5:24 and 5:46 D27 grabs unsuccessfully at stringy fish guts while Mom continues to feed D26
6:25 Mom feeds D28 a small and large bite
6:34 the camera zooms in
6:55 the camera pans left
6:58 the gray speck inside the pip moves
7:05 D26 pecks at and pushes D26 down
7:16 Dad rolls the egg
7:20 the white piece of shell covering part of the pip is poked up by D28
7:22 Dad sits down on the hatchlings
7:27 the camera zooms out
7:41 Mom grabs some fish guts and eats them as Dad tucks in grass around the nest cup
8:08 the camera pans up
8:14, 8:42 and 8:50 Mom feeds D27 bites as Dad tries to settle in more on the hatchlings
9:47 D28 sticks his or her head under Dad
9:53 Mom flies off the nest
10:20 Dad finally finishes settling in on the nestlings