Trans-species Justice

A thought occurred to me: Rawl's view, as written in "A Theory of Justice", applies to fairness, as it is commonly termed, among human individuals regardless of race. It does not address nonhuman elements by any means. Yet there exist debates over animal rights. Where do animals fit into the scheme of justice as proposed by Rawl? 

Animals, whether they are capable of communication within the species, as elaborate of that of even a child, or even inter-species communication, are by their very nature not human. Similarities may exist, with or without said communication. Some level of emotion may be felt, social structures are present (Wolves for example), so too basic needs. Much of Western society would not give any credit to the statement that animals deserve the same basic rights as any human being. Surely politics could not be included---we cannot communicate with dogs, one of our closest animal companions (bar countries that see them as viable food sources) so we cannot speak to them and give them the pros and cons of voting for any particular candidate for any election. We would not give animals the same rights. 

Then how would a person who believes in reincarnation (typically not a mainstream Western religious feature) deal with valuing the rights of that same dog. That dog may once have been human, who did not quite live up to expectations on the way to enlightenment and escaping the reincarnation cycle. By debt of not having lived a better life did that being (dog) forfeit basic rights? Ignoring the political ramifications, does that dog deserve total freedom of person, the right to some basic level of autonomy and power---the right not to be eaten? 

Yet, even before this becomes an issue we are brought to the question---with all of these possibilities how does that play into the original position? Behind the veil of ignorance each mortal being (for presumably all are mortal, reincarnation or no) has to face the possibility that they may believe in reincarnation (whether it truly exists or not, belief is belief). Thus, technically speaking all creatures on earth might be given the freedoms of a human being. Or we must affirm that by not being human in the present life, freedoms are restricted, as in a caste.  

Clearly if the first were so, we must kill other potential-humans in order to eat, essential to life. That act would deny the basic rights of those who fall into the category of presently-nonhuman. If the second were so, that gives some precedent allowing caste and social classes to have an effect on our existence and our basic rights. It would allow for inequality. 

Perhaps there is a way to argue that the cases are not alike, and thus separate answers are allowable. Disputing the likeness, or even throwing out Rawl's theory seem the most likely to me. That or somehow we know divine truths, but not our situation in life, behind that veil of ignorance....

I don't really have an answer, to this, by the way.