Given the damage I’ve seen done to roadkill my area, I’m not sure how you would distinguish between “entrails pulled out deliberately” and “guts squeezed out and dragged along the road by tires”. Roosters being birds and thus somewhat fragile for their size, getting run over smashes them pretty completely and distorts the carcass.
On the other hand, if the corpse is intact enough to identify it as a rooster it may not have been run over, or just got a glancing hit from a vehicle.
Cockfighting roosters typically have their combs removed (less for an opponent to hang on to, I guess - I am not, nor do I want to be, an authority on cockfighting) and thus may be harder to identify as to gender - I’m curious how the person in the e-mail is identifying the bird as a rooster as opposed to a chicken, but I’ll go with the assumption the birds are indeed roosters.
My experience with Santeria and Voodoo is limited but I DO know there is a larger than most people realize community of both, as well as Ife, in Chicago. What I do know indicates that sacrifice of the rooster is usually by twisting the head off (a lot quicker than you might think IF someone knows what they’re doing) and not ritual disembowelment. Most animal sacrifices in those religions are eaten, and thus would be disemboweled as for any butchering operation, but then they would be EATEN, not tossed in an intersection. I am not aware of any ritual that calls for disemboweling of a non-eaten sacrifice.
However, there are a lot of imitators of Voodoo/Santeria/Ife that could result in such things.
It would be helpful to know of any patterns in placement, drawings underneath (Voodoo makes extensive use of “veves” or ritual drawings), whether the roosters tend to be of a particular color, and so forth - things that might be difficult to see or unsafe to investigate in a busy intersection.
There is also the “escaped rooster” angle - in my area the local chickens do get out. In fact, just down the road from me is a rooster who, when he gets loose, stands in the middle of the road and challenges passing cars, including spurring the front bumper. It’s a wonder he hasn’t been found flattened in the road. But roadkill chickens tend to get flung to the roadside, not the middle of the pavement. Predator-killed chickens also tend not to appear in the the middle of roads, either.