Epictetus begins the passage by contemplating how the beasts need little and how everything is provided for them to exist. furthermore, he expresses gratitude that humans do not have the responsibility or worry to provide for the animals, as everything they need has already been provided. for this "order of things" we ought to give thanks.
also, we ought to contemplate these seemingly minute details and be grateful to the gods for them. it is fascinating that from grass, we have milk; and from milk, we have cheese. from plants we have clothes, gasoline, energy, modern transportation, communications, medicines and much, much more. by our creative and innovative natures, we are able to create an abundance and provide for many. for all of this, we ought to be grateful to the gods. and just as many people have conceived of an idea and created some system, so too we ought to appreciate the many natural systems that have been created in the world; from the generation of food and animals and crops to the self-healing nature of oceans and land.
by today's modern standards and our very diverse social world, there is one odd observation Epictetus makes - that of facial hair and voices. he observes that facial hair on men comes from god, so that people can distinguish between male and female. nature has also given women a "gentler note into their voices" and are "deprived" of facial hair. he concludes that it is "only right to preserve the signs that have been conferred on us by God" (v. 14, p. 38).
the conclusion and point of the entire passage is about expressing gratitude to the gods. "what else should we do, both in public and in private, than sing hymns and praise the deity, and recount all the favours that he has conferred! as we dig and plough and sow, oughtn't we to sing this hymn of praise to God: 'Great is God, for having provided us with these implements with which we till the earth; great is God for having given us hands, and the power to swallow, and a stomach, and enabling us to grow without being conscious of it, and to breathe while we're asleep.' this is what we should sing on every occasion, and also the most solemn and divine hymn to thank God for having given us the power to understand these things, and to make methodical use of them" (v. 15-18, p. 38).
later he says, "if I were a nightingale, I would perform the work of a nightingale, and if I were a swan, that of a swan. But as it is, I am a rational being, and I must sing the praise of God" (v. 20, p. 38). this passage reminds me of Martin Luther King Jr. when he said,
If a man is called to be a street sweeper, he should sweep streets even as a Michaelangelo painted, or Beethoven composed music or Shakespeare wrote poetry. He should sweep streets so well that all the hosts of heaven and earth will pause to say, 'Here lived a great street sweeper who did his job well.'meditating about these things and then feeling and expressing gratitude about them, makes us healthier and happier. a simple web search will return many results of studies showing these benefits (see this link). this one particular article notes 31 benefits of gratitude. big or small, go ahead and recognize and express gratitude for all things you observe.