The discoveries are prompting concern from residents and an investigation by the Montgomery County SPCA.
"It's almost like losing a piece of myself, to be honest with you," the turtle's owner said.
"I'm in agony," Paula Rodriguez said. "I've been living a nightmare since Friday, knowing my baby is out there somewhere scared, or might be injured. All kinds of thoughts come into my head and I can't do anything. Every minute feels like a day."
The all-volunteer foster-based operation is facing a 'crisis point' in their quest to leave no dog behind.
The dog is a 12-year-old Akita German Shepard and weighs about 80 pounds.
Ryder has a microchip, making it easy for the shelter to track down his owner, who said he got out of their Las Vegas yard on July 3.