Diarrhea/dirty vent in mature hens UPDATE

[JennsPeeps]

Look for posts about sour crop - that explains that issue.

BOSS - black oil sunflower seed

 

[Firefly]

I know it sounds awful, and it's not pleasant for either of us (me or the chicken), but it works: I hold the hen by the feet, upside down, and squeeze the crop and throat to empty the contents out through the mouth. It only takes several seconds-- not long enough for the hen to aspirate on the contents.