Paraffin oil is far from ideal and may not be very good for your hen.no I use paraffin oil because I have been recommended by a girl not to use olive oil because it affects the liver.
Try and get some coconut oil. Put it in the fridge until it solidifies. You can then feed your hen lumps rather than try to get a semi liquid down her.
Unfortunately crop problems are often symptoms of other problems rather then the problem itself.
You might want to consider a routine such as this.
Flood her crop with plain water. Here is an article on how to crop feed.
https://www.backyardchickens.com/ar...dications-to-all-poultry-and-waterfowl.73335/
I aim to get at least 40ml into the crop. The crop should feel full and watery.
Gently massage the crop to mix the water in with whatever solids are left in the crop. Check any poop for consistency. Taking pictures may help.
After half an hour or so feed her the cold coconut oil. Try to get around two centimeters square into her.
Massage the crop again.
Let her rest for a couple of hours and repeat.