I would do what is necessary to get rid of them before finding out. It totally depends on the situation on any given night (or day) and you can never predict that. I am brand new to hunting, but not to seeing what wildlife can do to domestics. Comparing what happens between a given dog (or dogs) against a single coyote or two when it is not a "planned kill" is apples and oranges when it comes to a pack of coyotes who have figured out the territory and decide it is time to get rid of what they might decide are competing predator or just a pain in their tail.
I went through a similar thing after my VERY large Maine Coon cat was killed by a fox. I hadn't found this site yet and was doing internet searches trying to find info about cat-killing foxes and how to get rid of them. Instead of finding what I needed, I found people saying how foxes wouldn't bother a large cat because it would be too much for them to deal with (claws, teeth, and size), and how they had watched their cats chase off foxes, or even share food. After looking further, I found that many of these people were in England, and the situation is much different over there. The foxes are so spoiled off of eating garbage and so on that they just don't attack cats much, if at all.
My cat got out of the house one night, and that is all it took. After learning more, I think that the pair was teaching the pups how to hunt (my husband walked up on one that did not want to stop feeding, and saw two others hanging back a bit). After killing four foxes since then, none weighed near as much as that cat (~10 lbs versus 20 lbs for the cat, it didn't matter)
On the coyote side of things, it depends on location, the pack situation, the time of year (if they are raising young ones), how desperate they are, etc. Your dogs could be fine for 364 days a year, and them boom, they are gone. We have heard of several large dogs being lured away and never see again during mating season. We see many "lost dog" signs posted during that time of year.
JMHO, good luck!