Pelleted and manageable

The Burgess website As well as an unlimited supply of hay or grass, you can give them around 30 grams of pelleted food per rabbit every day.  I feed Burgess excel pellets, as recommended by my vet, but your vet might either recommend or sell you the food they think is best.

Some rabbits have digestive problems and therefore can't eat pelleted food, instead, replace the pellets with a larger quantity of green vegetables such as kale, cabbage, broccoli or cauliflower leaves.

Hay, grass and more hay

The most important part of any rabbit's diet should be an unlimited supply of grass or hay.
If the rabbits have lots of hay, they will get thirsty, and therefore need a constant supply of water (which they should have anyway).

Grazing time is recommended for all rabbits (weather permitting) as fresh grass is better than hay in most situations.
Because rabbits need frequent exercise anyway, it is easy to solve two problems with a few hours in a run placed onto the lawn.

For health reasons, not all rabbits should eat grass, the very young and those producing large quantities of caecotrophs should be provided with hay instead.