If you are connecting the 6V from the 4 AAs to the micro's raw pin, that's not enough, needs 7 to 12, try 6 AAs (9V), do NOT connect to the 5V (Vcc) pin. Where is the servo power coming from? Not from the 5V pin I hope, it cannot supply current for 2 servos, 1 is really too much and 9V is too high for the servos, get yourself a 5V, 2 to 3 Amp wall wart.