Thanks for the support everyone. This morning about 6 I went out to check on everyone. The mother hen that went to bed injured was dead in the coop. I was by myself yesterday and tried to examine her and get ointment on her injuries, but this morning my husband looked her over better and we found a wound that I had not seen yesterday.
Neither baby that was lost last night was back this morning. So we lost a total of 5 baby chicks and one grown hen. Sad chicken day for us. They are locked up in their secure run, will add some things for them to do later and figure out securing the outer run better so they have the option for more space. We will look into the electrified poultry fencing. I think I found an area where the babies may have accidentally gotten out and then maybe gotten by whatever. Of course out of the 2 babies remaining I'm 99% sure one of them is a rooster, bummer, we just want laying hens, I'm scared of having a rooster around small human children (almost 4 years old and 15 months).
I suggested hardware cloth to the outer less secure run (has deer netting now, more to hold them in because we haven't had a predator problem since getting them a little over 2 years ago), but my husband doesn't want the high cost involved. The sudden large loss is tough for me to swallow, but I guess it's part of it.
Side note, we have a sand box that we filled with corn for the kids to play in instead of sand, and the last 2 days the lid was taken off, so I'm wondering if whatever is getting in that is what decimated my flock or if it's something else. We've had that out there almost a year and nothing has bothered it until 2 days ago.