I've never kept any more than two, and my mum used to dog-sit mine and my sister's dog alongside her own, although that was only during the day. Even so, she is herself in her 70s and can't do this any more. She can barely look after her own Jack Russell but will not entertain any idea that this is the case. But if she ends up in hospital again, we're going to have to find another home for him, I reckon, lovely as he is and much as we'll miss him.
I guess this woman has 'collected' these dogs with the best of intentions and now cannot bear to part with them, believing that some terrible fate will await them if she does. Age will blind her to the fact that she herself is doing them no favours.
But as Ummmm says, there has to be concrete evidence that this is actually what's happening and that a few vindictive, possibly dog-hating neighbours aren't just spreading nasty rumours. Even for a top trainer, keeping twenty-odd dogs quiet in their living quarters 24/7 is nigh on impossible, as any police or military dog trainer will tell you.