Or to avoid her kicking the stable you could feed her tied up on the yard or in the field, not sure how you would go about stopping it though
Carpet or mattress infront if it's only one area
if she does that during eating only you might gonna have to look at the whole enviroment? is she agressive when she does that? could she potentially be feeling a bit nervous that someone will take it off her or that other horse will eat it instead? is it possible that she doesnt like the horse thats next to her? Have you talked to your vet (it might be ulcers)?