I'm a little confused by the feeding guidelines as it says a 4 pack is a week's supply, and mentions that a bunny will eat a cube in 2 days but then goes on to say that, if you feed a cube per day, that your bunny will be healthy. So, is it 1 per day or every other day?
Going by Gray's estimates, 2 bunnies consume around 10kg of hay in ~ 20 days, which is 500g per day. If they ate one of these cubes each per day (500g) that would equate to the same amount of hay that they're currently eating. If they're only fed the lower amount, they would only be eating around half the current intake.
It says that it's compressed strands of long fibre hay, so I would be interested to see the actual product. I don't think I would feed it instead of hay (as I probably couldn't afford to for starters :lol
but I think it could be a good addition.