I wish... I studied/researched coyote in graduate school and grew up in Florida with feral pigs being both an immediate issue (destruction of our yard), as well as a greater environmental issue. Currently live in GA and have a good number of friends who have to deal with feral pigs as part of large scale natural resource/land management. - I've never come across any research, evidence or verifiable anecdotal evidence of coyote predating on feral hogs.
Feral hogs can be very tough customers and under the right circumstance pretty aggressive when attacked. (ever see the gear that pig-dogs wear when running hogs?) On the other hand coyote tend to be very resourceful and diet-adaptive creatures. I tend to suspect a feral hog could give a coyote(s) a very very bad day and it would be less easier/risky for coyote to pursue alternate food sources.
If you're talking about domestic pigs.... I dunno... that would someone else's area of knowledge.