Answer:
The detail from the passage that supports the claim that this is an allegory for the Great Purge is: the protesting hens being intentionally starved.
Step-by-step explanation:
The Great Purge, also known as the Great Terror, was a period of political repression and persecution in the Soviet Union during the late 1930s, in which many people were arrested, imprisoned, or executed. In Animal Farm, the hens who protested against surrendering their eggs were punished by having their rations stopped and were intentionally starved. This is similar to how people who opposed the Soviet government were punished by being denied access to food and basic necessities during the Great Purge. This detail reflects the themes of repression, persecution, and propaganda that are central to the allegory of Animal Farm.