ACV will not treat a yeast infection, it is more of a preventative. Does her breath or the liquid smell sour? Acidified copper sulphate is one of the recognised treatments for sour crop.
No sour crop should not be contagious but if there is a problem with their diet or the feed, then it is likely to affect more than one of them. Have they have access to any fibrous material like longish (4+ inches) grass or hay or straw. Is their feed in good condition and in date.... hasn't got damp and gone mouldy. Did they run out of food? Have you been feeding them bread or scratch grains? Do they have access to grit? These are things that can cause their system to get out of balance.
Be very careful when you are massaging her crop that she doesn't inhale any of the refluxing liquid as that will make matters a lot worse.
Good luck with her and let us know how you get on.
No sour crop should not be contagious but if there is a problem with their diet or the feed, then it is likely to affect more than one of them. Have they have access to any fibrous material like longish (4+ inches) grass or hay or straw. Is their feed in good condition and in date.... hasn't got damp and gone mouldy. Did they run out of food? Have you been feeding them bread or scratch grains? Do they have access to grit? These are things that can cause their system to get out of balance.
Be very careful when you are massaging her crop that she doesn't inhale any of the refluxing liquid as that will make matters a lot worse.
Good luck with her and let us know how you get on.