Mandates methods and practices for animal euthanasia in all public and private agencies sheltering stray or owner-relinquished animals. Requires mandatory holding periods and conditions that must be satisfied before any animal is killed. Mandates shelters to develop and follow care, cleaning, and disease-prevention protocols. Requires funds collected from dog license revenues to be used for free and low-cost animal sterilization and medical assistance programs. Requires that most animals adopted from specified agencies be spayed or neutered prior to adoption. Creates reporting, tracking, and notification requirements. Establishes private enforcement authority. Summary of estimate by Legislative Analyst and Director of Finance of fiscal impa...