"Adoption days" refers to specific days or events on which people can welcome a new pet, usually from a shelter or rescue organization, into their homes. Full definition
We often bring the rabbits and small pets who do best at adoption days,. (petesgrillandpizza.com)
And I hope pet stores also invite those rescues in for adoption days too! (ewao.com)
Occasionally, rescue groups will transport their adoptable animals to our building on adoption days with the hope that loving homes will be found for the animals. (hendrickscountyhumanesociety.org)