Here is something i found. But ive never treated it.
Impacted or Bound Crop in Chickens by Cara & John Harrison
Causes of Imacted (or Bound) Crop
Impacted crop (crop bound) is similar in cause to sour crop in that the crop does not empty overnight but in the morning it will feel hard and swollen, like a golf ball.
In both cases the bird is likely to seem lethargic, will lose weight and may make strange head movements due to the discomfort of the crop
What is the Crop
The chicken’s crop is located right beneath the neck against the breast and just right of the centre.
When a chicken eats the food goes into the crop, which extends to accommodate the food and, especially with young chicks, can be easily seen protruding after the bird has eaten. For more information see Crop Problems in Chickens
Treating Impacted or Bound Crop in Chickens
If you suspect your chicken has an impacted crop start treatment in the morning by dropping a small amount of olive oil or liquid paraffin (2-3ml) into the bird’s mouth and then gently massaging the crop to help break up the compaction and repeat this procedure in the afternoon.
Feed a soft food such as layers mash and again add some natural yoghurt to soften the food and neutralise and bacterial build up in the crop.
It may take a couple of days to break up the compaction, but if it persists for three days the compaction may need surgically removing.Ideally take the bird straight to the vets where they can perform the operation. However, if a vet isn't available then you may need to undertake this yourself to save your bird's life. This raises a dilemma as we've been emailed by a vet to say that it could be construed as causing unnecessary suffering to the bird unless you can anaesthetise it.
So in that case it would appear that if you can not obtain the services of a vet (perhaps due to economics or lack of a vet with the requisite skills in your area) your legal option would be to humanely cull the bird. Accordingly, this information is offered for interest only and not as a suggestion of what to do
To carry this out operation yourself you would need a scalpel, rubbing alcohol, cotton wool, clean towels, water, saline solution (at blood temperature), an additional pair of hands to hold the bird securely and superglue.
Firstly wrap the chicken in a towel and hold securely. Next, locate the chicken’s crop and sterilise with the alcohol and then make an incision about half way down the crop of about 1cm using enough pressure to cut through the skin and the thin muscle area below.
Once the incision is made quickly remove the contents of the crop and then rinse the crop with the saline solution. Put a thin line of superglue along the incision and hold the edges of the muscle and skin together so they seal. Superglue was actually invented as a method of treating injuries on the battlefield for the US Army.
Clean the exterior area and again rub with the alcohol solution. Isolate the chicken in a clean secure coop and do not give any food or water for at least 18 hours. After this provide water and small amounts of liquefied food such as pureed fruit or mash.
If you suspect infection go straight to the vet for further treatment. Always seek the advice of a vet if the condition worsens.
Anyone have any good advice. Something you have actually done that has worked. 
