Hens Not Using Nesting Boxes

So last year was my first year keeping chickens. I had 6 egg laying hens who all laid, reliably, daily eggs and from the very first egg always used the nesting box with only one or two exceptions where the egg was laid just in front of the nesting box.

While I built a coop and run that I thought was pretty secure, I made the mistake of stapling hardware cloth to the frame of the building and some snow and ice built up over winter and popped a few staples. A qeasel for on through this new,.small hole and killed my flock. I have since put strapping over and wages on the hardware cloth to secure it to the building.

Now I have four new pullets and they have been laying for a few weeks. I have the same nesting boxes with straw and some decoy eggs in them but the girls have never gone near them. The started out laying in the poop below their roosting bars (I assume they just dropped them as they roostes). Now they are flying on-top of the fees box I built and laying them up there. Some roll or get knocked off the top of the box and drop and break in the coop.

I have 8 more hens I am raising from chicks and I don't want these pullets teaching them bad habits so I want to get them laying in the boxes soon.

What can I do to encourage them to go in the nesting box? Should I put some treats in the boxes until they start going in them? I don't want them roosting or popping in them, of course.