Feeding outside strays and they haven’t been up in a few days…

So my dad has been feeding the outside cats in our backyard for about 3 years now. It started with one female, Ashley. She had a litter, raised them, abandoned them, and disappeared. The babies stuck around, and my dad kept feeding them and trying to gain their trust. About six months later, Ashley came back with another litter. Our neighbor actually managed to trap one of the kittens, and my dad caught the other. Both the kittens live with us, have been fixed, and are doing very well.

About six months after catching the second litter, (about a year ago) we trapped the male of the first litter. A month after that, we caught the female. They were both fixed, and also have taken very well to being inside-only cats.

We, and our neighbors, have attempted to catch Ashley, but she is extremely elusive. We all understand that it’s more likely we would be TNRing rather than bringing her inside to live (though we’d be open to that if she was able to acclimate), but in the meantime, she’s had yet another litter.

These kittens are probably about 2-3 months old. They’ve been coming up for dinner every night since early December, and my dad has managed to get them to hang out in his garage with him. They have an outdoor insulated cat house, and have a cat door to get in/out of the garage.

The problem now is that they haven’t been up in about four days. There’s one male cat, Nick, who comes up every night, and he’s still around. He has a skittish temperament and always got along fine with Ashley and the babies. We probably have coyotes/foxes, but I haven’t seen any in 10+ years, nor has anybody in my small town. The weather has also been much milder in the last four days than the past few weeks generally.

I know it’s difficult to speculate and impossible to know for sure, but does this sound like a situation where something might have happened to the kittens? Ashley has disappeared for months at a time and then popped back up, but the kittens have never stayed gone for so long. Thinking about going out and looking for any signs of them tomorrow, just looking for reassurance or maybe just some cold hard truths.