Sour crop is a fungal infection of the crop
If your chicken has sour crop you will notice her crop increasing in size, sometimes up to the size of a tennis ball!
Some chickens still want to eat, but are usually lethargic. They tend to move their heads from side to side as if to shift or try to swallow something. Please remember Sour Crop can cause death and should be treated as quickly as possible.
Treatment of sour crop
You need to turn her carefully upside down and empty her crop of all the liquid contents by massaging it from the bottom to the top. You need to do this quite quickly though, to prevent her from choking and to also prevent any fluid entering her lungs.
When you feel the crop is empty, you will probably still feel some grit like substance at the bottom. Its best to then isolate her from the rest of the flock.
At this point you may wish to visit your vet for a course of Baytril to treat the fungal infection. For further home treatment, find yourself a syringe and cut the end off and feed her some natural live yoghurt (about 5ml-10 ml) each time three times a day.
You may find her crop keeps filling up with fluid, so you may have to repeat the emptying process every morning. If this does not do the trick, add a couple of large cloves of garlic (ground in a pestle and mortar) into a couple of tablespoons of the live yoghurt and carry on the treatment. Garlic has anti-fungal properties, so can make all the difference.
If her crop reduces in size you will find she will become hungry. So feed her porridge mixed with live yoghurt and banana. A little olive oil will always help things move along.
After a day or so, you should be able to put her back with the rest of the flock. If in any doubt it is always best to consult your local vet.