One of my RIR pullets has had this exact problem for the last 4 or 5 days. She passes poo, but she strains very very hard and it extends her vent tissue at least a 1/2 inch off her butt, making the area raw and painful looking. Once she is "done" with a bout of this, her vent looks OK but still swollen.
The molasses has worked a little bit, as did running her butt under warm water for while, but nothing has cured it and she is noticeably smaller than the other chicks her age. I fear that her chronic constipation is affecting her growth and/or nutrient absorption. She is now three weeks old.
The other chicks (I have 7 others) do not seem to care about her problem- I've observed no picking of her vent or anything else unpleasant.
If anyone has a good answer to how to fix this, I am very interested!
(Oh yeah- and I tried separating her from the other chicks and she screeched non-stop for a few hours. I decided it was not worth it after that, and put her back in.)
-MTchick