Daft ?

One of the ex-battery girls has been a bit depressed lately, she is eating and drinking ok -even had some worms and dandelion leaves today.
Keeping an eye on her - they are all (ex battery's) 18mths old.
Her poo is blackish with a little white on top.
Im just wondering if the stress is catching up with this girl.
And another one seems to be napping quite abit - tucks her head on her back - like my budgies do. This one naps during the day whilst all the others are scratting about, etc;
Ive bought some cider vinegar (the horsey one) to put in their water but cant seem to find the post which said on how much to put in (slow band is such a pain -cant get broad band here- we are in a vale) :?:
One of the ex-batts is getting so brave that she comes to stand in front of me and watches me for ages - called her Indie - she looks like a little indian as her tail feathers stand right up  

Thanks for that munty