As a JW I would have allowed it. Carnivores including dogs do not drain the blood of their prey before they eat.
The JW doctrine of abstaining from blood even for medical treatment was scripturally and biologically debunked decades ago. Watchtower knows this. But they have too much blood on their hands and fear additional lawsuits from families of deceased witnesses who died refusing blood transfusions. So they double down. They use fearmongering to dissuade rank and file Jehovah's Witnesses from objectively researching anything critical of Watchtower. 1 Thessalonians 5:21 and Proverbs 18:17 says they can do just that.
It is also noteworthy that Watchtower formerly prohibited organ transplants having cited them as cannibalism. This also led to the deaths of obedient faithful witnesses. Their permission for the use of blood fractions requires blood donors. Hence it is nonsensical as Watchtower often is. That is not to say JWs should not use them.
Exception to the law to protect life:
There was absolutely an exception to the law including regarding blood and the Sabbath. It is a Rabbinic provision known as “Pikuach Nefesh”. You can Google it. It is based on Leviticus 18:5 and 19:16. NO One was required to die for the law. Life and well-being trumped the law.
In keeping with Pikuach Nefesh Leviticus 17:15 Permitted the eating of meat with blood in it when no other options were available. It permitted eating recently killed animals. The only caveat was that they bathe in water after eating the unbled animal.
According to the New Testament Jesus- who practiced Judaism, applied Pikuach Nefesh to break the strict Sabbath to help people. This also applied to helping animals. See Matthew 12:11-12.
It is also noteworthy that breast milk contains Millions Of White Blood Cells. This one fact invalidates Watchtower's blood prohibition.... Regardless, Pikuach Nefesh is the exception to the law. Protection of life and well-being trumped the law. 1 Thessalonians 5:21 and Proverbs 18:17.