Small baby, but healthy. Did not have rds so why did they intubate in dr?

Multiple options. The only way to know for sure is to ask the doctor. The most common reason to intubate in the delivery room is if the baby isn't vigorous and meconium (stool formed while in the uterus) was noticed before or during delivery. They briefly intubate to suction the newborn's lungs in case they breathed in (aspirated) some of the meconium. In that situation the tube is taken back out immediately.