Ononesto's "happy" paints a small, bright picture: a group of sheep dancing across a field. The speaker watches them with obvious affection, calling them "lovely" right away, and the poem never moves far from that warm, admiring view.
What stands out is how the happiness spreads. At first it belongs to the sheep and their "happy feet." Then the grass is happy too, as if being stepped on by dancing animals were a gift rather than a bother. The word "tame" is a nice choice here. It suggests the sheep gently smooth the grass, not crush it. By the end, the speaker widens the circle to "everyone," which could include the reader.
The repetition of "happy" and the plain, short lines make the poem feel childlike, almost like a song or nursery rhyme. The mood is cheerful, calm, and uncomplicated. It asks us to enjoy a moment of simple joy without looking for anything darker underneath.