Animal Welfare Professionals

Does anyone know of an animal sheltering timeline that exists that shows key milestones in animal rescuing? I've found some dates like the first spay/neuter clinics, the publication of ASV guidelines, etc but wondered if there's a timeline that exists (not for a particular rescue organization, just for the field in general), to show the evolution of animal sheltering. 

Hi Leslie, The ASPCA has a webinar you may find helpful about the History of Animal Welfare (https://www.aspcapro.org/webinar/20120111/history-animal-welfare) - the pdf of the slides lists some years of when animal protection laws were passed and animal welfare groups formed.  

Thank you so much!!