Almost all versions of the story end with a line of dialog from the country mouse, explaining why he prefers country life to town life. Horace's version for example, ends with "‘I have no desire for a life like this; and so farewell: my wood and cave, secure from surprises, shall with homely tares comfort me." The version presented in Fables Every Child Should Know, two thousand years later in a very different format, ends with "I am going back home. This is fine house, and there are many good things here. But I could not enjoy them, for should always be in fear and danger. I like better to have plain food and to live in peace and safety."
Of the 56 versions in this collection, only 6 lack an ending line like this, and most of those are extremely unusual variants where, for example, the country mouse is eaten.
My textual analysis skills aren't currently good enough to extract meaningful information from involved analysis of this section of the story, but such analysis is possible using the datasets I have provided on the collection, which have a special field for the last word or closing line. The best I can do at present is render a word cloud using a tool called Voyant, which presents the most common words used in each variant, minus some words that are very common in English (like "the").
The word cloud is an easy way to visualize the three biggest trends I've observed in transcribing the text of each fable:
1: The country mouse often makes mention of a stereotypical country food ("I much prefer my humble peas...") and occasionally does so in contrast to a stereotypical town food ("better beans and bacon...than cakes and ale.")
2: the country mouse typically makes mention of where he lives in the country ("cave," "hole," "hollow," ect).
3: the country mouse typically has a humble or conciliatory tone, rather than a confrontational one. Usually, he just wants to get back home.