you do not give probiotics daily or on a regular basis. Bene bac is the best probiotic for a rabbit and its a good thing to have on hand. We have a couple of tubes of the paste and this is the easiest form to give it. We buy ours online. Ive also seen the powder form at a local pet store.
Giving probiotics during a diet change, times of stress, or if you notice loose stools are the best ways to use them.