LilCtryGal, continue with the vinegar and yogurt for several days. you want to see improvement in his processing of feed. Continue to gently massage his crop for several days also. Let us know how he is doing. PM me if you need more help.
The apple cider vinegar you use needs to be the natural ACV with the cloudy "mother" in it. It will have more of the good bacteria you need for your birds. The processed ACV removed the "mother". A good variety is Braggs but any ACV that says "natural" or "mother" on it is okay.
Also, if...