Farmer Maggot's Dogs

[Inziladun]

First off, there's no evidence that the dogs ever "savaged" anyone. As Frodo said:

'I daresay the beasts knew their business and would not really have touched me.'

And as Pippin noted,

'But after all, folk down here are near the border and have to be more on their guard.'

So yes, I think Maggot was reasonable to keep dogs for that alone, mushrooms aside.

As for the Ringwraith encounter, it was hardly likely to end in death. They were in the Shire covertly, and I can't see them killing any hobbits just for grins.