My budgies have started to make a sound similar to hiccups. Honestly it could be anything like sneezing or coughing but they look completely healthy, if anything their more active. They're still not tame so I'm reluctant to take them to the vet, I don't want to risk losing trust for a false alarm.
I have the radio on almost all day for them, so I guess they could have learnt a new sound or something. The sound is hard to describe so I'll try and get a video.