>> Either you are watching constantly, or you are very lucky with the timing,
Believe it or not mostly a fluke. Although I was watching earlier, a friend round was round this afty but after they'd gone at about 6ish, I saw your post so decided to look at the cams again, which is when I got the pics of the empty shell.
After that I did "watch" for quite a while though (dual monitors so was able to keep it open whilst doing other things) which is when I saw the 2nd chick.