I love how the billboard shows multiple dogs and cats, as if someone worked out the relative edibility of various specific breeds. Golden Retrievers are slightly more food-like than Basset Hounds apparently.

shouldn’t rabbits be considered more edible than horses

Rabbits are more conventionally edible than horses, but the vastly higher pet-rating of rabbits compared to horses outweighs that. Plus if you really wanted to eat a horse they have more meat on them than a rabbit.