RABIES?......................
I would suspect rabies.
First of all, my experience with packs of coyotes in NH is that they are NOCTURNAL PACK hunters.
Meaning, if you let Fluffy the cat(or small dog) out at 11pm to pee before bed, it is quite possible they will be surrounded and killed by a pack of coyotes.
This also happens here with Fishers(also known as Fisher Cats). A member of the weasel family.
Coyotes that are out in the daytime hours are usually sick.
Attacking a child is also not normal behavior. This would be normal behavior for a Mountain Lion. Not for a coyote or even a Coy dog.
All of the Eastern Coyotes have dog DNA/breeding mixed in now. They are much larger than the Western Coyote.