Natural symbolism in the Twelve Days
This motley crew of also-rans have become minor Christmas icons, a supporting cast to the festival’s leading lights; Rudolph, the robin and the turkey. The cumulative song, à la Old MacDonald had a Farm, dates back to the 16th Century. The claim that it was used to promulgate forbidden Catholic teachings seems odd, because the doctrines mentioned in it were held by papists and reformers alike. Perhaps the jingle enabled Catholics to recognise and communicate with each other, a sort of vocal equivalent of the Masonic handshake.
The meaning of some of the symbols is fairly obvious. The three French hens, for example, might represent the Magi or their gifts. The suggestion that the hens stand for the persons of the Trinity seems too blasphemous to be considered. The four calling birds were almost certainly the four evangelists.