ft asks-
should you immediately follow up with the Ki Yi to call in the mate?
We are talking about Coyote...
I think that depends on what you feel comfortable using. I usually just keep using the same calls and same cadence after a kill (any predator). Am usually using 2 or 3 mouth calls at a setup. By that, actually using/blowing 2 or 3 different calls. Have so so results with calling after a kill or miss. I did kill a double the other weekend and had two other setups with another Coyote about, but didn't get 2nd shot. But...
There are some factors to consider when killing or calling multiples.
Animal density is first on the list. The more critters in an area the more the competition and the easier they are to call to gun or to trap multiples. Many times litter mates run to the call 'shouldering or racing' it's litter mate. Much like a young brace of Beagles 'shouldering or racing' on the scent of a Cottontail.
There is no better time of year to kill multiples than right now. Sure gives a guy some confidence and gives him a false sense that he knows something...LOL.
Other factors to consider on animal density...rifle Deer season...I have experienced Coyote (Fox too, to a degree) shift their range and consentrated on dense cover or areas that aren't Deer hunted. Breeding season...Multiples are running together or trailing one another.
The kills count. The call in's don't. Learn from both. Think what happened, how it happened and why in happened.
ft, I do use the Ki-Yi. Crit-R-Call. Got my first Crit-R-call from Willis Kent, goverment trapper out west. I can make alot of sounds on my Crit-R-Call and it's always with me.