If I understand your point correctly, I think the current wording is actually accurate.

Rashi discusses the Mishnah's list of Tereifos that apply to birds, explaining that they generally apply to animals as well and why they are repeated. However, he does not explain whether the specific case of a bird that fell into a fire and whose intestines changed color also applies to animals.

The Insight's question is precisely whether Rashi intentionally omitted this particular Tereifah of a bird because it does not apply to animals, or whether he omitted it for some other reason. The discussion that follows addresses exactly this question: the Rambam and Rosh maintain that this Tereifah is unique to birds, while the Ra'avad and Rashba maintain that it applies to animals as well.

Kol Tuv,

Aharon Steiner