Credible resources promoting early spay/neuter in shelter scenarios.
Please visit these links for information.
www.sheltervet.org/assets/docs/position-statements/earlyagespayneuter.pdf
www.adoptapet.com/blog/what-is-the-best-age-to-spay-or-neuter/
pets.webmd.com/dogs/guide/spaying-or-neutering-your-dog-faq?page=2