You can click on the visibility dot for each. You can also click+drag to change many dots at the same time. If you use the tree filter to only show bones, it is easier to hide many bones with click+drag.

What is the reason for wanting to hide a bone and all the children?

Didn't you recently make it a feature to right click on a visibility dot to hide the bone and all its children? (in the editor, not in the data)

I found it quite useful for working on certain parts in isolation (ie, avoiding clicking on things I don't want to click on)

Ha, yeah I did and forgot about it.

Pharan please check your PM's

I'm sorry to resurrect an old thread; but I'd like to mention that this feature isn't yet on the Cheat Sheet.
I myself was looking for it and had to dive into the forums to find it was already implemented

We'll get the cheat sheet updated

Bumping this again, since I was searching for this, too. My question is, can I animate the visibility of a bone and all it's children?
In our case, we are doing some canned movie-like sequences where multiple characters are interacting in one big Spine animation. We need one of the characters to appear half way through the animation, but so far the only way to do this is to animate every attachment under that character's top bone.
(Same problem with color and transparency, actually - can't do it to a bone and all it's children.)
Any chance this ability will ever come to Spine?

There are cases where you would not want to hide all children which is why it was set up like it is now. However maybe we can come up with a way for you to hide a bone and all it's child slots by using a modifier key when you hide it. Something like Alt+LMB on the visibility dot.
Let's see what Nate thinks.

Thanks. Ideally, looking for a way to animate bone visibility (and color/alpha) and have it affect all it's children.

Click+drag doesn't seem to be working anymore

Fixed in 2.0.18, thanks!

Thank you! Much appreciated.

Thanks for this.
Just wanted to refer to this very similar question, but with a use case where ticking on and off a lot of slots is not preferred:
viewtopic.php?f=11&t=576&p=18458#p18458