allad:
1.
a. A narrative poem, often of folk origin and intended to be sung, consisting of simple stanzas and usually having a refrain.
b. The music for such a poem.
2. A popular song especially of a romantic or sentimental nature.
from The Free Dictionary

1.
any light, simple song, especially one of sentimental or romantic character, having two or more stanzas all sung to the same melody.
2.
a simple narrative poem of folk origin, composed in short stanzas and adapted for singing.
3.
any poem written in similar style.
4.
the music for a ballad.
5.
a sentimental or romantic popular song.
from Dictionary.com

1
a : a narrative composition in rhythmic verse suitable for singing
b : an art song accompanying a traditional ballad
2
: a simple song : air
3
: a popular song; especially : a slow romantic or sentimental song
from Merriam Webster

It seems that the word 'Ballad' is generally accepted as meaning a verse form intended for singing. On the basis that Kipling had a good knowledge of the english language I base my comment that "The presence of two volumes of 'Barrack Room Ballads & Other Verses' would suggest that Kipling aimed at having these sung."