How do I know if my chickens have sour crop?

Typical symptoms of sour crop are bad or sour smelling breath, with general lethargy, lack of appetite and an enlarged crop (may feel gassy or fluid filled). It may be possible to observe lesions in the mouth and oesophagus, but these are typically more prevalent in the crop and so are not normally visible to owners. Young chicks and growers are more susceptible, but it can also affect mature hens. If you suspect your chicken has sour crop please seek advice as this should be managed by your vet.