Shelters across the US are struggling to take in a growing number of dogs and cats. Some pets adopted early in the pandemic are being sent back as owners slowly return to normal life. The financial impact of Covid-19 as well as a puppy boom due to a pause in spaying and neutering during the pandemic are also adding to the strain. "It is so hard for the animals," says an employee of Lucky Dog Rescue, a Virginia-based non-profit that matches shelter dogs with temporary homes.