I would be very careful with turning her upside down and massaging the crop. Chickens can breathe in the fluid and die very easily.
You said that it feels like it is full of air or liquid and squishy, I would smell her breath to see if it's sour. Impacted crop would I think have a hard ball of long grass or other things jammed in there that you would be able to feel. @azygous wrote a good article on treating various crop ailments, though the dosing of miconazole will probably have to be adjusted according to her size.
I have emptied chickens with severe sour crop a few times by inserting a tube into their crop (down the esophagus) and either letting it siphon out (the end of the tube is lower than the bottom of the chicken's crop) or by syringing it out. After that, since in my case the hen wouldn't eat, I woud tube feed her with miconazole mixed in. Removing the fluid in this way prevents any possibility of the hen aspirating.
Also, I agree with everything the above experienced people have said, this is just my two cents. (I am open to opinions and corrections of course!)
You said that it feels like it is full of air or liquid and squishy, I would smell her breath to see if it's sour. Impacted crop would I think have a hard ball of long grass or other things jammed in there that you would be able to feel. @azygous wrote a good article on treating various crop ailments, though the dosing of miconazole will probably have to be adjusted according to her size.
I have emptied chickens with severe sour crop a few times by inserting a tube into their crop (down the esophagus) and either letting it siphon out (the end of the tube is lower than the bottom of the chicken's crop) or by syringing it out. After that, since in my case the hen wouldn't eat, I woud tube feed her with miconazole mixed in. Removing the fluid in this way prevents any possibility of the hen aspirating.
Also, I agree with everything the above experienced people have said, this is just my two cents. (I am open to opinions and corrections of course!)