Parol Evidence/Interpretation & Prior Negotiations Forum

[HiiPower2015]

I am a bit confused about the use of prior negotiations in order to interpret an ambiguous word. We have learned that the hierarchy for interpreting ambiguous words is express, course of performance, course of dealing and then trade usage. I assume that express means the other words of the K, but if I am wrong please let me know.

That being said, in the Frigaliment chicken case, the court looked to the negotiations of the parties to determine what they intended by the word chicken. How would prior negotiations fit into the four ways of interpreting ambiguous words? Would they be considered express, even though they are not in the final contract?