What a terrifying experience! But your efforts did save her life.
What likely occurred was she had impacted crop, and your massaging the contents probably shifted them to obstruct her airway. If you will recall the manner in which you massaged, was it lower down on the crop or near the top? And how vigorous was the massage?
At any rate, you managed to get her breathing again, and she should be okay.
However, you may not have completely cleared the impacted crop. To be sure you've sufficiently treated the crop disorder, I recommend giving a couple teaspoons of coconut oil in its solid state. It's much easier to give safely without getting any into the airway (which is at the center of the throat). Insert at the right side of the beak so it goes down the right "tube"(which is on the chicken's right side of the throat)
To massage, place your fingers on the fattest part of the crop lower down. Gently massage in a circular and slightly upward motion, careful not to elevate the contents any higher than mid-crop.
You need to monitor the crop in the morning to be sure it has completely emptied. If the crop stubbornly remains full of solid material, you can safely use a stool softener such as Dulcolax.
Once the obstruction has been cleared, feed water and chopped boiled egg. Greek yogurt or probiotics will restore good microbes in the digestive track.
