I wonder if there could be any nutritional value left for the pigs to benefit from.
Yes, they will benefit.
With my chickens when I butcher, I have one bucket for the true waste, stuff I'll bury in the garden or orchard. That's head and feathers mainly. Your pigs would eat them. I keep another bucket for bits the chickens will eat, fat and bits of tissue. This bucket included the entire digestive tract from crop to the rear end cut into 2" lengths, including contents. Testicles and lungs. What comes out of the gizzard but not the gizzard. Basically any soft material. I toss these to the surviving chickens after I've finished, but only what they can clean up before dark. I don't want to attract predators. The liver goes to the dogs but you can eat them or give them to your pigs or chickens.
I cut my chickens into serving pieces as I butcher because that is the way I cook them. The breasts, wishbone, thighs, and drumsticks go to the table. I keep the feet, neck, wings, back, gizzard, and heart for broth. To clean the feet I blanch them in hot water for a short time which makes them easy to peel and to twist the claws off. All this slows me down quite a bit when butchering but I'm trying to mention what can go in the broth. The pigs would eat some of this.
After I eat the table meat I save the bones in the freezer. These cooked bones add a nice flavor to the broth. I cook those bones overnight in the crock pot covered with water and save the water. I then toss those bones in the trash but your pigs will probably eat them. I freeze that flavored liquid and use it when I make broth instead of just water.
After I make the broth I strain the liquid through a colander to remove the big chunks. I pick through those chunks and save the meat. That cooked meat is great for tacos, chicken salad, soup, or on a sandwich for lunch.
I save the soft debris from the colander (I use veggies in my broth plus any soft stuff that is not meat) and use that in my traps. It is great for raccoons, possum, skunks, mice, and rats. I even caught a groundhog once but i think that was an accident, he just blundered in.
The only thing I consider that I waste is the bones after broth. With pigs you don't need to waste that much.
I'm sure your butchering will look a lot different from mine, with 50 you are in a hurry and you will have a different end use. My way tales time. Your pigs may not be able to eat that much at a time unless you freeze some. But maybe you can get some ideas from this.