I agree coccidiosis is a strong possibility. Aprolium (Corid) is critical if that is the case.
That bulge is her crop. Maybe she impacted her crop when she went outdoors. Is her crop emptying overnight? She may be starving, even though she is eating. Did she have access to grit? You may need to gently massage her crop, but take care not to aspirate her (don't let the contents come up and then go down her airway). Do you have any coconut oil on hand? If so, make sure it is solid and feed her little chunks. Don't force this. You can put little chunks in her beak.