Broody hen and 2 MEAN welsummers...need suggestions

I have a broody mottle Java. She is in the large community nest since it is the lowest to the ground. I have 2 welsummer brats that like to sleep in there at night. The nest is about 2 ft-ish by 3 ft-ish. Bessie, my broody, sits in a corner while the two wellies sleep on the other side. But occasionally, one of the brats will get up and peck Bessie on the head! One she can't take it anymore (she normally is not picked on), she moves to another corner and tries to take her eggs with her. She has left a couple behind on a few occasions. She is down to one egg now (the ones left behind are ice cold by the time I get there ). I doubt this egg will make it because the stupid wellies.

Before I continue, I would like to note that I want her to hatch in the main coop and raise the babies with the flock (if possible).

So, one idea is to put the dog crate in the coop and lock her in there until she nests and then give her all new eggs. But, the dog crate is used as the chicken hospital, so I will have to cross my fingers that no one gets injured or sick for 3 weeks. The other option is use the kitty crate...which seems too small to me (but I guess it is bigger than the 12"x12"x12" nests that some recommend using).

So, what do ya'll suggest? She is a good broody...not overly picked on, but not an alpha hen. These two particular welsummers leave her alone when she is out and about, but in that nest, they are nasty to her! They broke one egg and ate it (and we don't usually have an issue with egg eaters)! (it was at 8 days!).