Has my ex-batt just lost the will to live?

Hey everyone.  Lokking for some advice, as usual!  

I got my four ex-batts on 1 August and three have settled in well and are now well into their cunning plan to systematically destroy the garden.  Not that I mind, it's lovely to see them trashing the place.  Makes me happy that they have the freedom  

However, one of my girls, Mavis, has never really come out of herself.  As the others grw in confidence and scratched about, she just sat quietly.  She did get bullied and chased about for a while but now the others just seem to ignore her.  I have to fish her out of the coop every day, otherwise she'd just stay in there.  She does eat and drink (I put bowls all over the place for her) but not as much as the others and doesn't even stir at the sight of mealworms.

I took her to the vet last week because she felt hot and the vet checked her all over.  She said there was no broken egg, nothing wrong with her crop, no breathing problems, no swollen organs, no wounds, just nothing that could indicate why she had a temperature.   She also said there were no lice or mites.  She gave me some Baytril and Flubenvet.  I trust my vet - she knows her stuff and, despite admitting that she's not keen on chickens (just because she's a vet doesn't mean she has to adore the whole animal kingdom, I guess), she has a lot of experience with poultry and I don't think she missed anything...

A week down the line - no change.  We dug out the run yesterday to lay a new floor and the other girls went crazy - climbing on Hubby's spade and getting under his feet as they looked for worms.  They had a great time.  Mavis just hid in the wire run, which we had moved onto a another part of the lawn while we dug out the floor.

She spends most of the day sat under my daughter's climbing frame, with her beak tucked under her wing and her eyes closed.  

Anyway, I don't know what to do now.  She obviously isn't happy but I don't know if there is anything else I can do.  I could take her back to the vet and see what she says but I am wondering if she is one of these ex-batts that just "give up".  Perhaps this is more psychological than physical?  I am going to contact the Battery Hen Welfare Trust, as they must have experience of this, but I thought I'd ask here and see what you guys think.

Many thanks, Amanda x

Hi Amanda if in any doubt I would take her back to the vets - it may be something that wasn't apparent in her last visit. joy xx

I think I'd contact the BHWT and see what they say ...