Literary connections or mere Edyecatshin

An aul sayin that was a favourite of my uncle James was:

As fu as an egg's fu o meat.

"Did ye get enough ta ate?"
"I maun I did. I'm as fu as an egg's fu o meat"

Several years later (whilst studying for my A level English) I came across what I believe to be the origin of this sayin in Romeo and Juliet:

MERCUTIO (Act 1)
"Thy head is as fun of quarrels as an egg is full of meat, and yet thy head hath been beaten as addle as an egg... " etc.

This aul sayin (or at least a similar version) also crops up in W. G. Lyttle's Daft Eddie or The Smugglers of Strangford Lough

Chapter VII
"But then," he retorted, laughing again; "yer jist like a' the rest o' the weemin', as fu' o curiosity as an egg's fu' o' meat..."


Note: I am indebted to the Ulster-Scots poet Wilbert MaGill for the wonderful phonetic translation of Edyecatshin.