They are called "hens" because many years ago, lost an incredible Final to Peñarol 4-2 after leading 2-0Henhouse is another nickname as the home stadium
Lyrics
Gentlemen I am the henhouse, With River I follow where ever you go, No matter if you win or lose, Your fans always will support you, Go, go, River Plate, Put b*lls and heart, That is that is swollen, Deserves to be champion, In good go 'to be, And much bad, This gang will never abandon you... (Repeated...)