Origin of the saying " Bleeding like a stuck pig".

There are two versions, bleeding like a “stuck” pig, and bleeding like a “stuffed” pig. The stuck pig version appears to be the most common by far.
By all accounts it means to bleed profusely.
It would appear as though pigs, unlike other animals like sheep and cattle release a hormone when frightened, and this hormone “spoils” or “taints” the flavour of the meat. So, to avoid the bad taste, pigs are slaughtered as fast as possible.
There are two versions. One says a sharp knife is “stuck” into the heart of the animal, and then hung upside down to facilitate bleeding. This does not make all that much sense, as I would think if the heart is damaged the bleeding would be reduced.
The other, and more popular version is that the throat of a pig to be slaughtered is cut with a sharp knife, cutting the jugular vein. This causes profuse bleeding.
There is an abattoir close by to where I work, will pop in there and look and ask. Don’t think they still slaughter pigs in this way. Will find out.
amymeacham wanted to know where this saying came from.
Let me know if there is a phrase or saying you want to know more about, will go looking, digging and asking.