This link gives carbon to nitrogen ratios of various materials we compost -- with or without worms. Interestingly, there is no ratio given for pig manure. This is another url about pig manure:
(not a link: you have to copy & paste):

http://agrienvarchive.ca/bioenergy/download/F-1735_swine_man_char_OK.pdf

I didn't read all of the pdf about pig manure because it isn't my question. ; ) Something to consider might be that pigs have a more varied diet than horses. Thus, the ratio may vary according to feed. Pigs eat meat= protein -- which is not recommended for worms. Protein can poison red wigglers.
I don't know whether protein digested by a pig would have that effect.

If it were my decision, I would experiment: Try a little pig manure in a small vermicompost and see what happens.

lt appears that your composting will be outdoors. Please consider what leaches to the water table.

As far as the old vs new horse manure, the "expert" on this topic (IME) forum is Mendopete. If he writes in, take his guidance. His experience is that his worms like fresh horse pucks and he advises not to let it dry out too much because it is a little slow to rehydrate. If you are deworming the horses, consider that potentially toxic to red wigglers.

The important variable is the moisture level. You can either give the container a range, or you can have a moisture level as high as 90% -- as long as the worms have air and air that is not too hot. 70ú is optimum.

Good for you for reading up to find what you can before posting a question.

Here is a link that might be useful: C N ratios

Thank you for your response!

Our pigs are fed an organic diet and no meat. It's actually not recommended that you feed your butcher hogs meat anyway since you risk the chance of salmonella contamination. So that's not a big worry for me!

I also haven't wormed my horse yet as he's not showing any signs of worms :)

Starting off, I'll be using 30gallon plastic bins for my composting, but if all goes well, I may move it outside. Like I said, we're new to composting and gardening so I don't want to bite off more than I can chew right off the bat! (We've already got more animals than I originally intended lol).

My biggest issue is going to be keeping the temp. under 95 as I live in Arizona and our temps are still in the 100's right now. I don't have a garage and keeping them in my house isn't really an option space wise.

Anyway, I'll experiment with the swine manure at some point and post how it goes!

I have heard of or read of someone using swine manure with good results. I do not remember any of the details.

Use your horse manure. One horse will keep your worms happy. I have about 250 sq.' of wormbed surface area to handle the manure of our horse.
Aged manure is better for starting a wormbed. It should be wet well (easier said than done). Allow it to heat up and then cool. 6" in the bottom of your bin is good for starters.
Once your bed is established, fresh manure can be top-fed. Don't mix fresh manure into any wormbed, only a few inches on top. Candy!

For some great ideas for outdoor vermicomposting in a hot dry climate, search out sierrawormsolutions. They have some free info about bin designs and are located in Reno.

Good luck and happy wormin'

Pete