Reference: Makaarim al-Akhlaaq – Page 46
From the best of manners is to be lenient with both humans and animals under your ownership. So being lenient with the human beings under your guardianship is to feed them as you feed yourself, to clothe them as you clothe yourself and not burden them with that which they cannot bear.
And being lenient with the animals under your ownership, inclusive of those which are used for riding or milking; each one differing according to that which you require them for. So in winter you place them in a warm place if they cannot bear the cold, and in the summer in a cold place if they cannot bear the heat. And to provide food and drink if they cannot take care of themselves. If the animals are from those which are used for carrying people (goods), then not to overburden them with that which they cannot bear.
This is indicative of the completeness of the Sharee’ah, and that it has not left anything out, even the creatures. Rather, it has allocated for them their rights.