The law for humans is based on the defense of interests. In the case of animals, this has also been regulated in the Health and Welfare Law for Animals, the Law against Laboratory Animals and the Flora and Fauna Law. Animals, however, cannot stand up for their own interests and it is very difficult for humans to express those interests for them. For humans, the priorities are mainly freedom and finances. In the case of animals, money never enters the question, nor does freedom, strangely enough. At least that is how it seems when we consider that humans rarely stand up for animal rights.  Humans do speak out where visible animal suffering is evident, but that is not enough to be able to speak of rightful treatment. Five fundamental freedoms have been formulated for agricultural pets, which cater for most animal needs, also for freedom of natural behavior. Humans mainly leave it at that.
The needs of housing, food and drink and prevention of diseases in animals are generally well catered for by humans.  When this is not the case, others, rightfully, become indignant and Animal Protection Authorities will take action, where necessary. But the freedom of an animal to live in conditions where it can behave naturally often falls short of the mark, in spite of the fact that this is regarded as a constitutional right.
Perhaps people have a blind spot for this. We know that, in order to maintain our freedom, we often need to make choices. Also, some fundamental needs, such as hunger and thirst have such a high priority that others fade in significance by comparison.  Such matters are, however, normally well regulated: even on a global level, a surplus of food is more of a problem than a shortage.
It is in the interests of both humans and animals, that they have sufficient food, safety, rest and relaxation. In adulthood, humans desire a family life, but  the majority of production animals do not get that far: as soon as they are fully grown or milked out, they are slaughtered.  They have reached their (final) goal. Killing animals is not pleasant, but is logical in an economical production system geared to meat consumption.
As most animals die so young and protection of production animals often stops by prevention of visible suffering, the majority of humans are unaware of the invisible suffering of animals.  It is difficult for humans to imagine that not being able to behave in a natural way can be torture for animals. We humans have, after all, been raised from a young age to live a life in which all naturalness has faded into the background. We humans can live with this, because we are able to influence it.   
By removing production animals and many house pets like slaves from their natural environment and keeping them away from it, we have taken away this influence from them. The natural environment becomes smaller and smaller and the living space is sometimes so small that animals such as the orang outang and polar bears are safer nowadays in Zoos than in the natural environment. Many meat-eaters reckon “they have a much better and safer life than in the wild”?
Along the way, the Earth has become so small, that some truth seems to appear in the reversal  of cause and effect. But what we are actually doing, is turning the world of justice upside down.
In our efforts to obtain so much freedom for ourselves, we have soiled the quality of living space of others. When freedom is increased in the correct manner, this should include increase of freedom of all concerned.
To make a firm stand for animal interests, we should strive for the freedom of animals to fulfill their natural needs themselves.

This is the space afforded to an organically-raised Dutch pig in order to fulfill his or her natural needs: a run with concrete Floor.
This is the space in which Danish pig farmers allow their organically-raised pigs to move around outside.