I'm never quite sure how to phrase my view without causing either offense or eliciting angry reaction from a particular section of society that believe they have the right to treat the other creatures on the planet, and the planet itself come to that, however they choose.
I find myself caught between two opposing views, neither of which I support.
On the one hand there is animal rights movement which in general I detest and on the other hand, as mentioned above, there is the human rights view which I also detest.
I'm rather fond of crocodiles.

They haven't changed much in thousands of years. Evolution got the design right from day one more or less. I don't keep crocodiles, not so much because they are dangerous but because I don't have suitable keeping conditions.
How does one judge what are suitable keeping conditions? Best option is to look at where the creature thrives without human intervention.
Of course, there are countless arguements that follow the reasoning that we are now farmers, chickens are not jungle fowl anymore, we need to feed lots of people, modern chicken breeds don't have much in common with breeds from their point of large scale domestication, etc etc.
What studies have shown is essentially the chicken has changed very little in natural behaviour and biology since it was first domesticated, bar the amount of eggs the hens lay. Their appearances have changed with breeding but how they think if you will, hasn't changed very much. They can and have adapted to a vast range of keeping conditions, with some negative consequences, but they survive.
Not one single person on this forum that I can think of
needs to keep chickens. They keep chickens because the
want to. There are lots of reasons why people want to keep chickens, many of those reasons when defended fail on logic.
I've worked with chickens kept in battery sheds, free rangers from small tribes to a large free range farm, tribes on a small holding and now Ex Battery and Rescues.
I would love to keep my own chickens but I haven't in the past because I have not had what I consider to be the right circumstances, not so much for me but for the chickens; wrong climate, not enough land, not enough money, too many predators...
So, I'll start with this basic proposition based on what I have observed about chicken behaviour.
Keeping chickens permenantly confined to a coop and run is an act of cruelty.
We (humans) carry out endless acts of cruelty so different people will have different sensitivities to it, but that is my basic view.
Next because there are different types of coop and run the act of cruelty is lesser or greater.
One is left with "I used to beat my children every day but now I only beat them on the weekends" type of defense for such acts.
I don't expect anyone else to adopt my viewpoint but it would be great if people would consider the basic propostion and learn a bit more about what the chicken is and what it wants before they get some. That's what I try to do here on BYC. I try to get people to get to know something about who and what the chicken is from my experiences, the various science experiments and the various studies.
It is interesting to note that many of those here on BYC with experience and educator badges keep their chickens free range, or in vastly better conditions than average. I might suggest that the more time one spends with chickens the closer one gets to my basic proposition.
However, in the last couple of years I have found an exception where I would consider keeping chickens with less than the optimal circumstances and that is when it comes to Ex Battery hens and rescues. The plight of these creatures is so acute that just having a patch of grass to walk on is such a major improvement in their lives that the ideal becomes almost irrelevant.
It seems probable that in the not to distant future I will break my lifelong rule and I will pay for some Ex Battery chickens in order to preserve the chicken keeping tradition at the alloments. There are a number of reasons for this but the main one is the allotments are one of the very few urban areas where one can keep a rooster left in the area. I have just about enough money to fund a small group and expand the keeping arrangements with the addition of another coop if necessary.