Does a hatching chick open the eggshell clockwise or counter-clockwise?
Why a circular motion at all? I think they just keep pecking until they’re free.
Chicks like big peckers, I don’t think it matters which way they turn.
No; many chicks peck a rather neat circular cut around the top of the egg, and pop the lid off. It’s a fascinating question.
Here is a picture of what the OP is talking about (sorry, it doesn’t answer the question of direction though).
WAG They oscillate back and forth?
Incubate a bunch of eggs, sit up and watch, then report the results. 
I don’t know how authoritative this is but…
This is talking about domestic chickens; it may not be the same in other species.
I was at the Michigan State Fair just last Friday, and was watching a quail hatch. It was about half way around when I started watching it, and it only took another couple minutes to finish. It went counter-clockwise, same as Mangetout’s source says, as seen from above.
It took a couple minutes longer to first get out of the egg, but it was in an egg tray, in the middle of a bunch of others, and fell back into it’s shell a few times.
Can anyone give us a cite from the Southern Hemisphere?
Great question ! Fascinating !
Thanks for digging that up, Mangetout. I hope Colibri sees this thread.