st witch:

"Where hast thou been, sister?"

the second replies:

"Killing swine."

It appears to have been their practice to destroy the cattle of their
neighbors, and the farmers have to this day many ceremonies to secure
their cows and other cattle from witchcraft; but they seem to have been
most suspected of malice against swine. Harsnet observes how, formerly,
"A sow could not be ill of the measles, nor a girl of the sullens, but
some old woman was charged with witchcraft."[68]

[68] See _Pig_, chap. vi.

Mr. Henderson, in his "Folk-Lore of the Northern Counties" (1879, p.
182), relates how a few years ago a witch died in the village of Bovey
Tracey, Devonshire. She was accused of "overlooking" her neighbors'
pigs, so that her son, if ever betrayed into a quarrel with her, used
always to say, before they parted, "Mother, mother, spare my pigs."

Multiples of three and nine were specially employed by witches, ancient
and modern. Thus, in "Macbeth" (i. 3), the witches take hold of hands
and dance round in a ring nine times--three rounds for each witch, as a
charm for the furtherance of her purposes:[69]

"Thrice to thine and thrice to mine,
And thrice again, to make up nine.
Peace! the charm's wound up."

[69] "Notes to Macbeth," by Clark and Wright, 1877, p. 84.

The love of witches for odd numbers is further illustrated (iv. 1),
where one of them tells how

"Thrice and once the hedge-pig whined,"

this being the witches' way of saying four times.

In Fairfax's "Tasso" (book xiii. stanza 6) it is said that

"Witchcraft loveth numbers odd."

This notion is very old, and we may compare the following quotations
from Ovid's "Metamorphoses" (xiv. 58):

"Ter novies carmen magico demurmurat ore."

And, again (vii. 189-191):

"Ter se convertit; ter sumtis flumine crinem
Irroravit aquis; ternis ululatibus ora
Solvit."

Vergil, too, in his "Eclogues" (viii. 75), says:

"Numero deus impare gaudet."

The belief in the luck of odd numbers is noticed by Falstaff in the
"Merry Wives of Windsor" (v. 1):

"They say there is divinity in odd numbers, either in
nativity, chance, or death!"

In "King Lear" (iv. 2) when the Duke of Albany tells Goneril,

"She that herself will sliver and disbranch
From her material sap, perforce must wither
And come to deadly use"--

he alludes to the use that witches and enchanters were common