Limping and straining to poop!!

[beach-bionic123]

Please help! Our chicken has been lethargic for a month now and we’ve tried giving her warm saltwater baths, syringes of water (sugar water as well), and generally giving her more attention. She’s really sweet and I’m not sure what to do. She’s been limping and seems to strain either pooping or laying an egg.

 

[beach-bionic123]

Here’s more photos: (Could it be the sun and is there anything we can do to save her?) thank you