Urgent! What do you mean, "the butcher won't eat pigs with hair after he dies"?

As the saying goes, "When a butcher dies, he has to eat pigs with hair". The pig killer died, no one took his place, no one lost his hair, so he had to eat pork with hair. There are all sayings of "United pigs" and "mixed pigs", which have the same meaning.

Describe the lack of an important link and the inability to do things normally.