If you have the means & ability to get her to a vet then you probably should; you shouldn't be able to hear her breathing. Thank goodness you rescued them!
Depends on the bird really. We clipped our White Leghorns' wings but they still went right over the 6 foot fence (straight up from the ground) like it wasn't even there. They are now confined in the covered grow-out pen.
We got chicks from Meyer & Mt Healthy and blooded them together with no problems. None were vaccinated and we used medicated feed. The only hatchery that we dealt with that vaccinates for Cocci is McMurray.
We didn't get Marek's vaccine because we already have unvaccinated birds and you can't...
Hoover (through TSC) was new to us this year; we got 20 assorted pullets in April and they are thriving. All girls & healthy from the get-go. We got eight different breeds so they gave a decent mix in the assortment.
I wouldn't think BR or Doms since I don't see a head spot. I am not familiar with Australorps but that could be a possibility. Either way, they are adorable. :love