We don't know about amount and timing of signs. It stands to reason the more of the affected foods eaten, the more severe the signs and the smaller the animal the less of the affected food required to cause problems. We've had equal numbers of cats and dogs (3 of each - suspects). VIN - the veterinary board I belong to is gathering information from their members and trying to collate information that could be helpful in diagnosing and treating this.
They are gathering info about how much was eaten, when and then lab test results and autopsy findings when the pet dies.
Doug