It’s not a mystery, they just haven’t named the species because McD’s violated the law on generic engineering. They were trying to get a pig with wings but got one with eight “vestigial” legs. Problem is Marvel invented, published, and trademarked Spiderpig™ decades ago as a fuck you to Johnny Gisnep. But chuck their mature eggs in a grinder and you get a nice smooth paste, like chicken nuggets, and they thought a rib mold they got at a garage sale the other day prior would work. You can see for yourself the disaster it wreaks as they have to build egg stocks back up between cullings.

Edit remembered Johnny’s first name