Arduino: Reading DS18B20 interferes with servo
Arduino's Servo library on AVR uses interrupts; if interrupts are disabled for any amount of time, the servos will twitch.

1-Wire protocol (used by DS18B20) needs to disable interrupts for the protocol to work. Therefore, servos glitch.

There is a great explanation of the problem here: https://learn.adafruit.com/neopixels-and-servos/overview , just mentally replace "Neopixel library" with "OneWire library". Their TiCo_Servo library sounds just like what you want.