Hiccuping chicken

[Nemesia]

Our pekin bantum Maud sounded like she was hiccuping yesterday, constantly, and it came from nowhere. Today she is hiccuping less but we are obviously concerned. They have apple cider vingear in their water, are wormed once a month and have tonic for 5 days of each month. She is looking healthy otherwise, her crop is empty in the mornings, she is eating, drinking and playing well. Her 3 sisters are also looking fine and not making any odd noises. They live in a raised house with a large run attached so can come out anytime during the day and they are let out to freerange daily.

After a search of the net on chicken hiccups - we are both more confused and worried after reading about gapeworm etc.

Any advice would be much appreciated! Has anyone come across this before?

Best wishes,

Nemesia