Legal Question in Family Law in Pennsylvania

It depends on what the contract says. If a contract says X agress to sell a dog to Y and it doesn't mention anything about being able to revoke the contract and the contract is otherwise valid, it can't then be revoked by X after Y has accepted the contract.

Now, if the contract was valid and didn't include any sort of clause allowing the breeder to revoke, the next question would be whether this would be worth the expense of pursuing. If a party breaches a contract, the only remedy is to file a civil suit. Civil suits can become expensive so it doesn't make sense to do this unless the potential recovery will exceed the costs. If the value of the contract is under the small claims limits, then the suit could just be filed at the magistrates office, which would be a much cheaper and easier way to deal with this.