x2If the liver had lesions, I'd be willing to bet it's blackhead. Another indicator is of course yellow poop, but so it cecal poop with blood. I agree that worming is a good place to start, but if it is blackhead, which it might not be, you'll need to find some metronidazole and figure out how to dose such a small bird.
-Kathy
Here's a link to dosages of medicines for pigeons. I've never owned pigeons or quail, but I figure they are both similar in size and weight. Included is dosage for metronidazole in case blackhead is present:
http://www.homingpigeon.com/article/Dosage.html