The chicken heart is bad, but I don't believe it could transmit a parasite to your polys. The digestive system of most fish can't properly break down all the proteins and fats in chicken, beef, and pork, probably most land based mammalian and fowl. This leads to fatty liver disease and other organ failure. Better to feed chopped fish, pellets, properly qt'd and treated feeders(sparingly) worms, some other insects. Mine do well on a multitude of pellets. I have 10 different uj polys and 14 rope fish. I've had the majority of my crew for over 4 years and they are happy and healthy on just pellets.
That is a crazy worm. I would assume every fish in the tank that the infected fish came from is also infected. I don't have a ton of experience or expertise in parasites maybe others could chime in on this with a proper course of action. ( Also on the possibility of the introduction by chicken heart)
When I saw the marks I thought for sure it was from one of the endlis. I'm not going to say it's 100% going to happen but you may want to find a different tank for the sen.