Church father St. Peter Chrysologus  denounces all sacrifices of animals.  From Sermon 108, "Man as Both a Priest and a Sacrifice to God,"
 
  "...man need not go beyond himself in seeking what he is to immolate to God!  Because man, ready to offer sacrifice to God, brings with himself, and in himself, what is for himself!  Because the same being who remains as the victim, remains also as a priest!.  Because the victim is immolated and still lives!  Because the priest who will make atonement is unable to kill! Wonderful indeed is this sacrifice where the body is offered without [the slaying of] a body, and the blood without bloodshed.  P. 169, The Fathers of the Church.  Saint Peter Chrysologus, "Selected Sermons," and Saint Valerian, "Homilies."  Translated by George E. Ganss, S. J. New York: Father of the Church, Inc. 1953.