What might account for both Mrs. Hale's and Mrs. Peter's initial differences and then their evolving solidarity with Mrs. Wright?
Initially, Mrs. Peters fulfill the role of dutiful, subservient wife. Mrs. Hale, a bit more outgoing and assertive, comes from a larger town, where the strict patterns of social norms in small towns are less evident. Both women plan to simply collect Mrs. Wright's belongings and wait for the men to collect evidence. However, it is the women who collect the most valuable item of all - a dead canary, and thus, a motive.
Unfortunately, the men are condescending to the women and women's "trifles" that they cause the women to begin thinking of what Minnie Wright's life must have been like. As they consider her childless, loveless plight, they come to the conclusion that her husband had taken her only joy, the bird, for no reason. Thus, they bond with the alledged murderess and keep the dead bird in the trifling knitting kit.