Change of Food for Rabbits

What do people/rescues do if a rabbit comes in with no food. How do they go about introducing a new type of pellets without upsetting the bunnies tummy?

even if mine come in with food (mix) i take them straigh off and put them on a very small amount of ss and lots of hay (which most have never seen before ) and have found that causes no problems, ss is fortifed with a probiotic anyway so helps to balance them out anyway!

should note that if you are not familairy with food changes or bunny sickness signs then gradually change food over a 10 days period!

SS is a good one to use or I just give lots of hay and a very small amount of pellets gradually increasing it over a few days.

When Rory arrived he was on excel and had LOADS of excess caecs so I swapped him straight onto SS and hay without any problems at all, and now he has lovely fat golden poos