That's a good option if the Humane Society does it for free. Ours charges a fee
ETA: It is absolutely not right that the pet store is allowing the rabbit to suffer. Although I would imagine they will euthanize her if she doesn't improve, since she's not going to be of use to them as a breeder and I'd imagine that, if they are keeping a rabbit as a breeder, they're pretty focused on profit.
But it's also not appropriate for someone to take in another animal, even for euthanasia, when that $40 (for example) could go to food or a vet visit for the 60+ rats.
ETA: It is absolutely not right that the pet store is allowing the rabbit to suffer. Although I would imagine they will euthanize her if she doesn't improve, since she's not going to be of use to them as a breeder and I'd imagine that, if they are keeping a rabbit as a breeder, they're pretty focused on profit.
But it's also not appropriate for someone to take in another animal, even for euthanasia, when that $40 (for example) could go to food or a vet visit for the 60+ rats.