X2 Definitely get a blood test before you start treating her, you don't want to run powerful drugs through her until you know for sure. A Vet can test for MS even some states County Extension will come out and test.@TwoCrows is more an expert on MS than I, but I doubt if you could tell if there was MS in those birds without a PCR blood test or a necropsy with testing. Zoologix will send swabs to self test for MS and MG, but the price may not be worth it to many. State vets may be less.
http://www.zoologix.com/avian/Datasheets/Mycoplasma.htm