Thanks for the link. There is a possibility she could have eaten something sharp. Wouldn't she be in pain? She acts fine except for not laying any eggs so after reading on this site I thought maybe worms. I did change her scratch around that time. I found a smaller bag of it at the coop and with just two birds I wanted to buy in smaller bags to keep it fresher. We had to dump out half of our last bag during the hot humid time of year.
Yes, she would be in pain. The muscles in the gizzard act constantly with a strong grinding movement, which means anything sharp would get completely stuck. But if she's acting fine that's probably not the case
And on your last comment -
She should have 'layers pellets' available constantly. They contain all a hen needs and she could live on them with nothing else at all. If you don't have one already, you should buy a feeder, as such:
http://images.google.co.uk/imgres?q...2&tbnw=131&start=0&ndsp=23&ved=1t:429,r:2,s:0 , fill it to the top, and leave it with her all the time. To make sure her water stays clean you could get a waterer too.
Scratch is all completely free-range chickens need, but not if they're kept in a coop.
At the moment, does she occasionally have large amounts of scratch? Even if you give her smaller amounts, if the intervals are too large she'll gobble it and impact her crop. Chickens need to eat small amounts constantly. I haven't read all the other comments on this thread, but if scratch is all you give her deficiencies could be a problem too.
Remember, happy hens lay more, so if it's possible let her free range more or if the dogs are a problem build her a bigger coop. We've just moved house, and ours had to stay in their little run for a few days. They hate it - two out of the three layers stopped laying completely. So happiness is also a big factor.
Try getting a 'flock block'
http://poultry.purinamills.com/OURPRODUCTS/Products/FlockBlock/default.aspx to keep her occupied and give her some seeds and things too. My chickens love lettuce, cabbage, pears and apples - take a whole one and secure it to the side of her coop for her to peck at.
As I said YOU REALLY NEED TO BE ABLE TO EXAMINE HER PROPERLY!
Could you possibly upload a picture?
I hope she's better soon!! D: