Why not continue with the chicken as well as the JWB? would that be possible? I mean, if they like the chicken, then it would be much better than a solely dry food diet, and if they will eat both then they'll be getting all the nutriients they need. Unfortunately its a myth that dry food cleans the teeth, in fact it has been implicated in poor dental health because the biscuits just shatters on the tooth and the debris accumulates around the teeth making a breeding ground for bacteria (although some of the dental diets have addressed this). The chicken, if you left it in chunks would actually be better for their teeth, gives them something substantial to chew on.