Watership Down has fabulous voice acting and solid animation that still holds up. Although it's rated PG, keep in mind this was 1978 - now this would be rated PG13 for violence.
The story follows the book upon which the film is based. A warren of rabbits are forced to leave their home and move elsewhere. Along the way are trials, tribulations and well...I don't want to spoil it. Let's just say that more than one scene will have you convinced that Monty Python's portrayal of rabbits might not be that far off - these little critters can be vicious.
The soundtrack also boasts an Art Garfunkle original "Bright Eyes" - which hit #1 in the charts in the UK, where Watership down was written, produced and directed. Within the context of the film, "Bright Eyes" is perfect - although outside of the film, it might be a bit dated these days (ymmv).
This should be available at your local library, or (I would hope) Netflix/Amazon Plus and the like.
Give it a shot and enjoy!