From Lady Wilde’s fascinating book, Ancient Legends, Mystic Charms, and Superstitions of Ireland (Dublin: Ticknor, 1887).
Weasels are spiteful and malignant, and old withered witches sometimes take this form. It is extremely unlucky to meet a weasel first thing in the morning; still it would be hazardous to kill it, for it might be a witch and take revenge. Indeed one should be very cautious about killing a weasel at any time, for all the other weasels will resent your audacity, and kill your chickens when an opportunity offers. The only remedy is to kill one chicken yourself, make the sign of the cross solemnly three times over it, then tie it to a stick hung up in the yard, and the weasels will have no more power for evil, nor the witches who take their form, at least during the year, if the stick is left standing ; but the chicken may be eaten when the sun goes down.