It could be retrained but I imagine you'd have to be quite strict with confining the dog in the house then letting it out and making a distinction between inside and outside. How they were kept/where they went to the toilet as baby pups also has an impact.
For what it's worth my adult dogs are in kennels/runs during the day and have been from when they were young and never, ever toilet there.
It's been my experience that there are clean/fastidious types of dogs who would be/do get upset to have to toilet in their own surroundings and dogs who don't care/go anywhere
Yes, you just treat them as a pup by restricting access to area and no free roaming, praise when correct.
As mentioned above some are much easier than others due to be naturally cleaner dogs and having been kept /raised in a cleaner environment.
My 7 year old GSD came to me at 8 months having lived in a kennel since birth. He was clean from day one and has never had an accident inside. His breeder did say he was clean in his kennel too so that may have had a bearing on it and I treated him like a small pup in terms of toilet training initially.
We’ve also had sheepdogs live in after living out without problems. Just treat as though they are a pup, take out regularly and especially on waking, after eating and playing. Praise when they toilet outside.
Hector was not house trained when we found him, the vet estimated his age to be between 3 and 7 years old. At first he just pee-ed wherever he wanted to, but we were very on the ball to have him out or confined to a crate unless watched like a hawk, so he became poo trained for outside quite quickly.
He is fine now. Took about 3 months for it to be reliable, but he was mostly OK after a month.
Sadly he is reliable at home, but still regards indoors anywhere else to be fair game, so no visits to pubs, friends etc!
It's totally possible. I've got one rescue who lived in a pound from 4wks old until he came to me at a year & a half ... he was was really easy, i think we've had two accidents in the following 4years ... & a 4yo who hasn't been quite so easy, but as WGSD says, we just treated as you would with a pup & she hasn't taken long. Both dogs still kennelled during day, in at night, & they know the difference.
Many ex racing greyhounds transition every year from being kennel dogs to house dogs.
Older dogs have the bladder control which a young puppy lacks making things easier. My advice is to take the dog outside every hour on its first day. It should wee due to nerves in new place ect. Praise and give a command, more praise. Crate overnight. Day two take out every hour and a half, day three every two hours. All mine have been house trained by then but they still have to work out how to ask to go out, so watch for restlesness ect until they work that bit out.
I re-homed a 13 year old springer that had lived in a shed all her life and she was clean in the house from day one. Just get into a routine and everything else will follow on behind.
New environments cause excessive (stress) drinking so over-weeing usually occurs but this will pass in a few days, as long there's no drama attached to it. Dogs are simple creatures at heart and one of those simplicities is a need to be clean, although the girl Willow may be the exception to that rule and thinks nothing of paddling in wee or poo!!
I have had 3 dogs that I knew definitely had never lived in a house. The first was Nina, my deaf girl, who spent her first year in rescue and the second, Joe, who was removed from a breeder at a year old along with 27 others, as they were being kept in appalling conditions. Both were clean in the house from day one.
The third was Layla, she had lived with the Travellers for her first year. She thought it was okay to pee anywhere in the house. It required more effort on my part but it really didn't take her long to become clean once she knew what was required and it wasn't a long term problem.