Philosophers have usually avoided arguing that all non-human animals have rights because:
the consequences are so limiting for humanity
it would give rights to creatures that are so simple that the idea of them having rights seems to defy common sense
The second problem is dealt with by not arguing that all animals have rights, but only that 'higher' animals have rights.
One leading author restricts right to mentally normal mammals at least one year old (called 'adult mammals' from now on).