Well-being, as defined in reference to one's welfare, is the condition of happiness, prosperity and good health. In dealing with an animal's well-being, there are two frames of reference to consider. First, biological well-being which encompasses the spacial, social, nutritional, behavioral and reproductive needs of a species. Secondly, cultural well-being of animals concentrating on their perception of happiness, cleanliness, safety and the way the animals are treated by the people who care for them.
In this paper, we are not addressing freedom as a condition of well-being, only happiness, prosperity and good health. Free-ranging wild animals are not free but are restricted by consideration of space, time and individual relationships (Hediger, 1969). We will look at animal well-being under these restrictions and discuss the effort needed to maintain well-being, as the level of constraint imposed by man on animals increases, and natural surroundings give way to artificial enclosures.
Lukas, J. (1995). Animal well-being in zoos, conservation centers and in-situ conservation programs. In A. Rowan (Ed.) Wildlife Conservation, Zoos, and Animal Protection: A Strategic Analysis (pp. 170-187).