If you mean to get rid of the fat?

Let it sit in the fridge overnight. That'll do it.

Oh, okay ... I wanted to finish the soup now so I was hoping for some trick I was missing. Thanks!

If you boiled skinless breasts, you might have a much longer wait than just overnight. There has to be some fat on the meat, to be temporarily emulsified by heat, for there to be anything to separate. If you boiled skinless, boneless breasts, you have something that, starting out, is about 1% fat, if that. You may not even see a layer of skimmable fat on a broth made of something like that. To get real stock, you need the approximate tissue makeup of a whole chicken, dark meat, skin (under which about 50% of a chicken's total fat is stored), white meat and bones.

If you start with something approximating a whole chicken carcass, in this day and age of water and brine injected commercial poultry, you'll wind up with 6 to 8% (by volume) skimmable chicken fat on top of your broth, when cooled to room temperature. If you're lucky, another 2 to 3% of "lighter" fat fractions (simpler fats with smaller molecular length that will remain semi-emulsified in your broth), giving your broth flavor and color.

I used (free range) thighs with bones and skin, so I think there will be some fat. (I prefer using a whole chicken, but didn't have one.) Thanks for the info -- I didn't know any of that. I didn't know there was more than one kind of fat in broth, and I didn't know that most of the fat is under the skin. And I definitely didn't know the proportions. (This internet thing, so useful. :)

Don't throw the fat away. Schmaltz (chicken fat) is absolutely fantastic for stir-fries, roast potatoes, just about any savoury dish where you need to cook things at a high temperature using a little fat.

Yeah I was gonna say, that fat is yor friend when you need fat. Tasty!

And Yum for home-made chicken soup!