Sounds to me as if she has some extra weight in her lower abdomen, like my pullet had. Feel her abdomen for a mass. She may be laying internally, which explains the tail down. Did you see her lay any eggs recently?
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Did you mean to say 'top left of her chest'? Because isn't the crop on the right? My girl does have a hard lump on the top left, but the bulging crop is on the right. Thanks.Have you felt her crop in the morning before she eats anything? If it is impacted then you will feel a lump on the top left of her chest. Normally the flat in the morning is flat then fills up as they eat. This can be caused by tangled grass or by gluten gathering from their food. This is a major evolutionary flaw in birds: there are no digestive enzymes in the crop so if something backs up here, it's not going to move by itself.
IF there is a lump there in the morning, you will need to break it up. This can be done by physically squishing the lump with your fingers (the windpipe is in the same area so be careful not to squish that!). Adding some proteolytic enzymes helps to break down the gluten and these are naturally present in pineapple, papaya and (I found out yesterday) kiwi fruits. My chicken was listless, tail down and reluctant to eat but no chicken can resist a mealworm so I pulped up some pineapple and kiwi with some mealworms, barley grains (less gluten than wheat) and her favourite budgie seed mix. Leave it to absorb for a while so she cannot help eating some juice. She might take little bits of fruit anyway if she fancies it. I did this over 2 days with crop massage as well. Put olive oil in the mix too, if you want. Try to get her to eat some before she goes to sleep and mush up the crop lump as much as you can. It can feel pretty solid and takes a bit of effort to squeeze it.
IF your chicken has a gluten impaction, this should clear it without needing to make her sick or using surgery.
I hope this is useful,
A chicken with her tail down is a sad, sad thing.
Good luck,
Kate