Seems more simple than it probably is, but I'm to understand that the hobs are like fairies or goblins and they, quite simply, set out on a quest to find gold.
They go out to find this gold, quite happy - singing songs and the like. However, when they arrive they don't find gold in the treasure chest, "only feathers".
They return to their barrows unhappy - "cry[ing] that old song".
Seems more simple than it probably is, but I'm to understand that the hobs are like fairies or goblins and they, quite simply, set out on a quest to find gold.
They go out to find this gold, quite happy - singing songs and the like. However, when they arrive they don't find gold in the treasure chest, "only feathers".
They return to their barrows unhappy - "cry[ing] that old song".