It sounds like you already have some good experience with crops, and I agree that I would not stick a needle into the crop for any reason. Perhaps the other poster was referring to draining fluid from the lower belly from ascites. Chickens don't need to be sedated for that or certain other procedures, especially since they can be very sensitive to drugs and painkillers. Tube feeding is very good to flush an impacted crop. Hopefully, you can figure out why her crop is not emptying. Two Crows and Casportpony have a lot of experience with crop problems. Worm loads, coccidiosis, Mareks disease, and other things can cause a sluggish crop.