The only record I have found with her birth date, is her 1925 death record from Vienna (indexed by GenTeam and accessed online at FamilySearch Centers). I have checked the JRI-Poland index and the Gesher Galicia index for both Feiga Freud and Feiga Bergmann (since her mother's last name had been Bergmann). I have not noted birth record for her in Obertyn. If you would like a copy of Feiga's death record, let me know.
~ Emily Garber
emilyhgarber@gmail.com
Obertyn appears as Feige's origin on her children birth records like this one -
http://agadd2.home.net.pl/metrykalia/300_new/album/971/#img=PL_1_30...
and on her marriage registration in Vienna.
I don't know where the exact date of birth was taken from.