Hi, Saturnix

Servos always have little movement at power up ... that's it !

For PULSOUT, just read ( very) carefully your manual,( Pulsout section + "driving large capacitive loads" section ) and you'll discover why a simple " LowPortX.Y" before PULSIN can avoid any signal problems.

Think to let a while to the servo-amplifiers to settle ...before asking them movements. The current draw, for few ms may reach 3/4 amp per servo ...
so, the PIC must have a private regulator to work properly.

Not so bad nor to have a separate batt just to feed the servos ...

For time interval, let's say signal period must be 20 to 50 ms ... for conventionnal servos, to have enough output power ;

a period change in that interval doesn't disturb too much the servo.

note a shorter period CAN be applied to "High end" Gyro servos ( 5 to 8 ms ).

For the end, Using the internal reset of the PIC is not a good idea here ... read µChip 16F84 Datasheet for info about reset circuitry.

read you next time
Alain