The 'mass' on the right breast area is likely the crop, filling when she eats and emptying when she digests. That is normal, and a good thing.
For the rest, I don't have much in the way of ideas. I would continue the vitamins and supportive care. Vitamin deficiencies can take a while to correct, if that's what it is. Also consider adding a straight B12 supplement to see if that helps. It could be a neurological issue, and some chicks just fail to thrive.
She may be developmentally behind. I'm pretty stubborn and don't give up on them easily, but that is up to you.
I'm attaching a couple of links on vitamin deficiencies, which may help: http://www.merckvetmanual.com/poult...ement-poultry/vitamin-deficiencies-in-poultry
https://www.tillysnest.com/2014/03/vitamin-deficiencies-in-backyard-chicks-html/
For the rest, I don't have much in the way of ideas. I would continue the vitamins and supportive care. Vitamin deficiencies can take a while to correct, if that's what it is. Also consider adding a straight B12 supplement to see if that helps. It could be a neurological issue, and some chicks just fail to thrive.
She may be developmentally behind. I'm pretty stubborn and don't give up on them easily, but that is up to you.
I'm attaching a couple of links on vitamin deficiencies, which may help: http://www.merckvetmanual.com/poult...ement-poultry/vitamin-deficiencies-in-poultry
https://www.tillysnest.com/2014/03/vitamin-deficiencies-in-backyard-chicks-html/
