Can Hens Count?
On one occasion the author found a hen disposed to set in a horse-trough. She had but eight eggs under her, and he added five more. The next morning he noticed that she had discarded five of the eggs; they were replaced, and were again hustled to the other end of the trough. He next marked the eggs, in order to discover whether she objected to the five eggs with which he had supplied her. At his next visit he found that she had once more rejected five eggs, two of which were marked and three not marked. She would accept but eight eggs, and was left to incubate in peace.