I learned this the hard way as well. I used to put my grass clippings in the yard when I mowed. The hens would eat & eat the grass. Last year, I had a pullet who ate too much long grass clippings and got an impacted crop. I separated her with only water.

I was about to attempt the surgery myself but talked to my regular dog vet who suggested that I first try this.

Using a plastic surgical tube (we had one for a human infant), open the bird's mouth; on the bottom of the mouth, make sure you see the trachea (windpipe) -- do not go near it! Instead move the tube along the roof of the mouth, down the throat all the way to the crop. My pullet struggled none after the tube was inserted. Then, with a syringe, shoot mineral oil directly into the crop. Massage the crop real good, gently. Do this twice a day for 2-3 days. Give the bird only water. IT WORKED!

I did not have to do surgery as this mineral oil worked after a couple of days. I no longer give my birds the grass clippings from the yard. I still give them grass at the end of the day (after they have ingested their grain feed) & I make sure it is finely cut.

I am very sorry for your loss.