While I agree that kapparot should be stopped (as many authorities throughout many generations have tried to do), it's important to cite the entire source in Shulh.an Arukh & Mishnah B'rurah. The Meh.aber does flatly oppose it, but Rema (R. Moshe Isserles' gloss of Ashkenazic customs) identifies it as a wide-spread practice "in these countries" and that is "should not be changed, because it is custom." Mishnah B'rurah gives the reason for the meh.aber's opposition -- "because of suspicion of the ways of the Amorite" -- but also gives a lengthier defense of Rema's statement.

Chag Sameah.