Stall rest is likely to just make the cribbing worse. If there was any way to turn her out to pasture to work off some steam and be a horse, I would do it. Also, movement usually helps wounds heal better as it keeps skin limber and pliable instead of healing really tight. Not sure what the injury is, but I would ask the vet for advice on turning her out.
IN addition to cribbing, stall rest can create enough stress to bring on stomach ulcers, esp if you aren't feeding enough bulky hay to keep her occupied. Hay can help curb the cribbing, by giving her something to do with her mouth. Hay buffers stomach acid to prevent ulcers,and any food should help with weight issues in some way.
It's hard to say without knowing your exact situation, too. I'm just stabbing in the dark, here.
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