What's the youngest it's OK to handle?

[anatess]

I'm probably about a year away from this point but I'm curious:

What's the youngest a hatchling should be when you begin handling them? I'm hoping to breed my two girls and I want to pick out a couple of choice babies to get as used to human interaction as possible from a very young age.

As always, thanks all!

Right when they get out of the egg and separated from their yolk!

Well, at least, in my case, I went and inspected each baby right when they got out of the egg so they got some handling. And then some more after that because I was replacing the paper towel often. And my kids can't help but handle them while I do all that.