Lame jersey giant hen

[Spurrberry]

Hello, I have a 5 month old Jersey giant hen. She suddenly started having a bad limp that progressed to splaying her legs forward and back. It’s not bumblefoot.Because she wasn’t making enough of an effort to get water and food and it’s super hot here I took her inside. She’s been resting in a kennel for a couple weeks and is just now starting to be able to walk again. She stopped eating for two days and was throwing up liquids, now she is eating normally and much more active along with walking(not very well but thousand times better), but still has liquidy poo.
Her sisters just started sitting on eggs and I’m not sure if they have layed any yet.

I’ve only once had a similar problem before with my silkie hen(who was reaching a year old and came from a different place), she did not have liquidy poo or throwing up, but she could not walk. She seemed to make some recovery and was starting to walk but passed away a couple days later.

Most I can find online is information about mareks disease.
Does anyone have any experience with these symptoms?

 

[Eggcessive]

It sounds like it could possibly be Mareks disease, but injuries do happen. She is at a common age for symptoms of Mareks to show up. The neural form may cause weakness to paralysis of one or both legs. The position of one leg forward and one in back sound familiar. Some birds with Mareks may have improvement, and later have tumors associated with the virus. A video of her walking uploaded to YouTube with a link posted here may be helpful. The only way to know for sure if it is Mareks or not, is to get a necropsy through your state vet lab if you lose the chicken. Testing is also done on blood in certain labs throughout the country. You would trim a toenail, and collect the specimen and send it back in. One lab is RAL here:
https://www.vetdna.com/application/forms/aviansubmittalform.pdf

Here is some reading about Mareks:
https://extension.psu.edu/mareks-disease-in-chickens