What does Mrs. Hale discover in the box in Mrs. Wright's sewing basket? How do the women respond?

Mrs. Hale opens the box to find a small dead bird, its small neck wrung brutally. The eyes of the two women meet with a look of mutual understanding. Suddenly there is a sound outside the door, and Mrs. Hale makes a rapid decision, closing the box and hiding it at the bottom of the sewing basket.