Best of luck...
I found where she had them. My husband has an old camper shell in a dilapidated shed along the fence line. I found the old clothes where she gave birth on them. No kittens. Either they all have died or she's moved them. After we buried the others she would disappear. Now, she's just laying out in the front yard. Unusual for her.
For those who suggested we catch and neuter them, we live in a rural area. Feral cats are a necessity to keep the rat population under control.
These wild cats don't starve. We stop feeding them scraps and cat food when we find mice in the house. They get hungry and start eating them again, then we start back with the food.