Although potato plants don`t mind calcium from the growing point of view, when tuberisation commences the presence of calcium in the soil can cause potato scab on the new tubers. Admittedly, with the small amount of calcium present in the chicken manure the scab is not likely to be serious and will often scrub off the tubers when they are prepared for use - some varieties, however, are more susceptible while others are scab resistant. Anybody growing potatoes for the first time, or who has not encountered scab before, however, may well get into a panic on seeing heavily scabbed potatoes, (one of my neighbours even called in a Min. of Ag Inspector when he got it and even after re-assurance binned the lot) and you are certainly better off without it than with it.
I certainly wouldn`t dig them up again, but if you find scab in your crop don`t worry, it shouldn`t be a bad attack and the scabs should only be skin deep and will either scrub or peel off.
