The hooves should be trimmed regularly.Also the water should be changed daily.If there is a strong smell coming from the hoof it can be treated with a medicine called Kopertox.
I know you can put thrush-x on them to try and help with them I also know you can wet the hoof and put lime on it. The best way to fo it is call the vet tell them your problem and they will be able to suggest some things that will help you to get rid of them.