Hiccups in dogs are often a normal reflex that can occur very frequently, especially in puppies and younger four-legged friends. Most of the time the cause is relatively harmless, but if it persists over a long period of time, it can also indicate an illness.
Puppies in particular often get hiccups because they take in too much air when they suck breast milk. Eating and drinking too quickly or excitement and stress are also among the causes - this applies to dogs of all ages.