Senior German Shepherd Pooping in the House Without Warning
I'm sorry. This is hard when a dog has been reliable his whole life. Pooping without warning, in his bed or while walking, usually means he isn't choosing to go indoors. It's more likely he can't feel it coming or can't hold it, so please don't punish him or keep him outside because of it.
In an older dog, especially a German Shepherd, the main causes to look into are nerve or spinal problems that weaken control of the anal muscles, bowel disease that makes stools urgent, and cognitive decline (dementia). Dogs with nerve-related bowel incontinence often leak small amounts of stool without noticing, and some also have trouble walking. German Shepherds are also prone to degenerative myelopathy, a slow spinal cord disease, so watch for scuffing back toes, wobbliness or weak back legs.
It's worth going back to your vet, or asking for a second opinion or a referral, and saying exactly what you've told us. A rectal and neurological exam, stool and blood tests, and sometimes spine imaging can find a cause. Some causes can be treated or managed, and medicine or diet changes may help firm up stools.
In the meantime, take him out more often, especially after meals and before bed. Feed meals at the same times, use washable bedding or pads, and keep him close to you so you notice when he's restless.
See bowel incontinence in dogs, degenerative myelopathy and dogs peeing or pooping in the house.
This is general information, not a diagnosis. Please follow your own vet's advice.
