Might be that only Jen and Penny know about it?
Let’s be honest here, Kevvie would spill, one way or the other.
If Bonnie knew about it he would have way more power over Penny.
Obviously this is just speculation and total guesswork based on the fact that these are mentally unstable people who have a lot of access to weapons.
It’s possible but unlikely that a field serf was shot by a paranoid Penny, but if there is a body there, I think it is more possible that Penny shot some poor sod who wandered onto the tranch.
Probably a drifter or hobo whom Penny mistook for a crack earl transphobe.
Even Penny would realize that telling Kevvie would lead to it being all over twitter, so perhaps he conferred with Jen.
As I say, utter guesswork and speculation and no evidence whatsoever, but their behavior is suspicious and I strongly think they are covering up something more sinister than a mass grave of alpacas