chicken additives

so, ruby was previously being fed purdue and tyson chicken quarters, wings, breasts.. normally i feed america's choice meats as they are cheaper, but sometimes the stores have a 40-50% off sale on purdue and tyson so i got those... since being on the turkey, she has not itched as much , which is a good sign. so someone said that the antibiotics and hormones in the purdue and tyson chicken could be affecting her, so i bought some america's choice chicken as the package said no hormones,additives or antibiotics.. she got one wing mid morning a few hours after her breakfast, and so far no scratching.. its trial and error, and so far the turkey which isnt purdue or tyson is working out very well, i am using Shady Brook turkey , and Weis ground turkey rolls as well.