A-Hunting We Will Go is a popular folk song and nursery rhyme by English composer Thomas Arne.
The a- is an archaic intensifying prefix; compare Here We Come A-wassailing/Here We Come A-caroling and lyrics to The Twelve Days of Christmas (e.g., “Six geese a-laying”).
Lyrics
Each consequent verse gets modified by putting in a different animal:
"...a fish and put him on a dish...""...a bear and cut his hair...""...a pig and dance a little jig...""...a giraffe and make him laugh...""...a mouse and put him in a house..."...Earlier versions of the song switch the words "a-hunting" with "a-roving", dating back to old roving drinking songs from the 16th century.
References
A-Hunting We Will Go Wikipedia(Text) CC BY-SA