I live in east Texas and do you know what is causing her poo to be green and runny? Also, she has been paler than usual and her tail seems to droop downwards.
Check her abdomen. Often when they get waterbelly (ascities) they have a hard time breathing and their energy drops. The fluid in their body - chickens don't have a diaphragm like people, so when they fill with fluid, their heart and lungs along with everything else is compressed. If this is the problem, it should be obvious - a swollen abdomen. At the bottom I've included a link to a very clear video of how to drain her. If she gasps extra hard if you pick her up and further compress her abdomen, her comb turns darker and she has a harder time breathing - it's almost certainly ascities.
If it is ascities, draining the fluid will HELP but it is NOT a CURE. There are risks in draining, of course - you are putting a needle hole so there's a risk for infection. There's also a risk that she goes into shock. But, if she's already miserable and can't be out doing happy chicken activities, the risk (to me) is more than worth watching her slowly declining.
I've got an old hen that I drain as needed - every 2-4 weeks -- and she goes on her merry way afterwards. Any time I see her start to waddle - her legs end up farther apart, she kinda does the John Wayne walk - it's time- other signs are unwarranted panting and darker comb, which means not enough oxygen.
I use a 14 or 16 gauge 1" needle because it's a bigger hole - anything like a 18 or 20 or smaller will take forever. Almost all livestock supply stores will have the 16 gauge 1" needle by their cattle health supplies. I don't bother with a syringe anymore- I either take the hen outside or drain into a bucket.
Here's the video- she breaks things down into easy to follow steps:
