I also have worked at different vet offices and honestly....I would not board at a vets.
The biggest problem for me is that usually the staff and everybody leaves at 6p.m. and then the dogs are alone till 7:30-8:00 a.m. the next day. This seems like such a long time to hold it.
I have had people tell me that their dogs got bladder infections while boarding at the vets....because they did not want to pee on cement...and held on for 18 hours.
Most boarding kennels have staff or the owners live there all of the time and the dogs usually get a chance to pee before bed.
Many vet offices do not have staff to be taking dogs for walks etc., especially if emergencies come in and everyone is busy.
The one vet I worked for, the usual routine was if their was time, the dogs got walked....if things were busy...then they had to pee or poop in their pens.
I think my own dog would explode before she ever went in a pen.
I would go with a dog sitting service or try to find a small boarding kennel where more attention can be given.
Gina