Help.

I need advice.

I have a broody hen...she has been broody for 8 days, 10-11 if you count the days I kicked her off of nest...anyhow...she was a great broody-I decided to do the whole broody adoption thing, with day old chicks. I put four under her last night(so day 7 of sitting on nest straight, 9-10ish for being broody overall). I know, that is early, and I was going to wait 2 weeks, but the chicks at feed store would not be there in a week, and I watched/read vids that said you could do it sooner as long as hen was for sure broody, and she was. Anyhow...it seemed to go great last night. I placed 4. They settled, and she purred. Then, this AM, I go out there and there is only 1 left. She is the ONLY one with access to nest as I screened her in. I placed a very small chick waterer in back of nest, and it was empty, so it must have gotten knocked around. Anyhow...I cleaned out nest and checked her over and I cannot find the other 3.

Where could they have gone? Could she really have EATEN them? How is that possible? They were probably 2-3 days old at most. The one I have left has a very slight red area on her toe-wondering if it is a peck...I tried to move her off nest to check her for chicks hiding in her fur, and she fought me back to the nest. She still wants to brood. She was not happy about seeing the chick left either.

She pecked it and then ignored it.
I feel stupid. But I need advice now.
1. Was it because it was too soon? Should I hold onto this chick and try again in a week? Or do you think she is just a homicidal hen that has lost her chance to brood, meaning I need to broody box her?
2. Can a hen eat 1-3 day old chicks with no evidence at all left behind?!
****ETA**** I found two chicks under the run! They managed to escape the top of the screen during struggle. I still have one chick totally unacccounted for.
Thanks