Visited a friend who keeps chickens yesterday, one of which was looking pretty poorly. The symptoms described sounded possibly like sour crop to me, with the hen regurgitating brown fluid and not eating, and generally looking unwell. I suggested the owners look for signs of canker, as this can cause a sour crop in pigeons, and i'm fairly sure is transmittable to poultry. Just wondering what the likelihood it is canker, or else what else causes sour crop, and what can be done about it (the hen looks very poorly)? I've read about apple cider vinegar in the water, also bicarb in water. I remember giving apple sauce to a juvenile pigeon whose crop wasn't emptying. Thoughts? Any info or advice appreciated on this.