Listen to the song here. The Foggy Mountain Boys was an American bluegrass band. The band was founded by guitarist Lester Flatt and banjo player Earl Scruggs. The group is considered one of the premier bluegrass groups in the history of the genre.
It probably means nothing. Yellow is the color we expect urine to be. If you take a vitamin supplement, these can sometimes give the urine an almost fluorescent color, a very bright yellow or yellow-green.
The yellow color in normal urine comes from a substance known as urochrome. Urochrome is also known as urobilin and is the result of hemoglobin breakdown. Hemoglobin is the protein in red blood cells that enables oxygen to be taken around the body.