同意王老师的分析。这里的 an entire flock of 与 a large flock of 同义，我查了一下 COCA，其中 an entire flock of 共8例，a large flock of共12例，从用法上看，两者均表示“一大群”。（以下例句供参考，请采纳王老师的解答）

an entire flock of：8例。如下：

(1) Think of it. Just one quiver of these arrows could decimate an entire flock of dragons. How are we gon na find her? …

(2) Took off on a perfectly clear day and injested an entire flock Of canada gees. The plane went down like a stone…

(3) Then, I met my alter ego -- an entire flock of flamingos! …

(4) When I got downstairs I realized AN ENTIRE FLOCK OF BIRDS had flown in the house. …

(5) In his sleep he had seen an entire flock of white birds with snapped necks, their blue tongues lolling out of beaks as…

(6) is suspended high up on the canyon wall like a modern Prometheus, an entire FLOCK of pteranodons gathering around him preparing to peck away his liver. …

(7) Were it not for my strange impulse, I would have massacred an entire flock of avian altruists as they huddled in sympathy around a helpless comrade. …

(8) The Professor's ambition was to count an entire flock of birds in flight so as to demonstrate the contrary of what…

a large flock of：12例。如下：

(1) her eyelid was jerking in an ever more agitated tremor, as if a large flock of white birds were flying inches from her face. Small wonder she kept tripping…

(2) A week ago Sunday, for example, we ran across a large flock of them living in (and flying through!) the densely wooded areas underneath…

(3) So if you see it like that each book purchased meant purchasing a large flock of sheep and the services of highly skilled labor for a substantial mount of time…

(4) At one point, I looked to the north and noticed a large flock of small birds headed towards me. I quickly grabbed my binoculars and found the…

(5) A large flock of European Starlings (also known as Common Starlings) at dusk over Rome…

(6) A large flock of starlings twist into ever-changing shapes as a peregrine falcon on the left heads towards…

(7) this pilot, this plane, had the unfortunate circumstance of plowing into a large flock of Canada geese shortly after takeoff, probably ingested enough of them in the engines…

(8) As she debated returning to the manor, a large flock of birds flew up from the lakeshore in a swirl of wings. She shaded…

(9) At first it looks like a large flock of birds swooping down, but then you realize it Is paper, thousands of…

(10) Their gazes were drawn upward for a moment as a large flock of birds cascaded down from the heights." Looks like it's about time…

(11) Then somebody has a large flock of worlds that need to be kept clean. An interstellar federation or union…

(12) and he was raising a large flock of white leghorns to make some money. One day, all the half-grown birds…