Do not offer up oil of any kind. It's very hard to digest and will slow down the crop even more. And I would not massage the crop unless the contents are very hard and stiff. Too much massaging of a liquidity crop can stretch the muscles.Over the weekend I did crop massage about every hour to 90 min... In the morning the crop feels swollen like a thick liquid with feed crumbles that I can feel at the bottom. As the day goes on every time I massage it, it seems to reduce down to a feel of wet but loose sand. It's much smaller than in the first 2 days of this issue, but still does not empty. Also in the first days she seemed very uncomfortable with massage but now seems to like it. Have given the acidified copper sulfate up to now, yogurt, olive oil mixed with mashed feed... Constant massage now about every 2 to 3 hours. I have her in the house in a crate because she seemed unbalanced on the roost and I also wanted to watch what she was eating.
So overall, smaller crop but not emptied in the morning.
Do you have any poop pics?
If her poop is moving fairly regular and look normal then she probably does not have an impaction.
Has she been wormed recently? Have you have Coccidiosis in the flock recently?
The only other thing I can suggest is a concoction I use on birds with stubborn yeast infections.
Only do this if you are comfortable giving liquids to chickens.
1/16 teaspoon Ginger Powder (you can even use the contents of a human Ginger capsule)
1/16 teaspoon Cinnamon Powder
1/16 teaspoon Cayenne Powder
1 teaspoon of Lemon Juice
1ml at a time, squeeze this liquid under her tongue 2 times a day via empty syringe for 3 to 5 days. I have seen the worst yeast infections dissolve.
You might also try Fluconazole, 5-10 mgs per pound of bird 2 times daily for 2 weeks. This stuff is slow to act but it works on some species of yeasts.