Why do the animals of Animal Farm want to keep the news of starvation a secret? What do they do to keep it that way?

Starvation loomed for the animals in Chapter VII of
Animal Farm. In addition to the destruction of the windmill, the
bitter winter included much sleet and snow. The animals were afraid that if the humans
discovered how weak they were, that they might try to retake the farm again by force.
So, they decided to take advantage of their only human contact, Mr. Whymper. Animals
would "remark casually that rations had been increased." The store-shed bins were filled
with sand and then feed was placed on top, making them appear to be well stocked. When
Whymper saw them, he reported to the humans that the animals were
thriving.