The elements and proportions of a rabbit's diet, the importance of hay, types of vegetables and dry food and feeding routine...
Feeding your rabbit the correct diet will keep it happy and healthy. Rabbits love to eat and in fact need to eat very regularly to keep their digestive system moving. The main bulk of their food should be hay or grass and they can spend literally hours every day eating this.
Most rabbits seem to prefer drinking from a bowl rather than a bottle but either is fine - you can get these from any petshop. The bowl should be heavy enough that the rabbit can't tip it over. The advantage of a bottle is that the rabbit cannot scatter food and droppings in the water. Whether using a bottle or a bowl, change the water at least once a day.
This should form the main part of your rabbit's diet, in order to grind down their teeth, maintain a healthy digestive system and reduce boredom. Approximately 80% of a rabbit's diet should be hay, to closely emulate the diet they would receive in the wild i.e. grass alone. Make sure the hay is not dusty and that it is sweet smelling i.e. not musty or mouldy. Most rabbits will happily eat any kind of hay but if your rabbit is fussy try meadow hay or dried grass.
You can feed a small amount, approximately an eggcup full a day for a small/medium sized rabbit, of good quality dry food in nuggets. This will provide them with the vitamins and minerals they need. Do not feed a mix/muesli as they will pick out the bits they like and leave the rest and therefore not receive all the necessary nutrition (this is called selective feeding). For baby rabbits and elderly / sick rabbits refer to the feeding instructions on the pack.
You can feed your rabbit a small amount of vegetables per day, about one or two handfuls. Dark, leafy vegetables such as spring greens and savoy cabbage are best. Spinach and kale can be a bit rich so only give these occasionally. Do not feed limp or wilted vegetables. It is a good idea to wash vegetables beforehand and avoid feeding direct from the fridge as the chill can upset a rabbit's stomach. Carrots are quite high in sugar as are fruits such as apple, pear, banana etc so only feed these in small quantities or as a treat.
Hay should be freely available at all times. Feed dry food and vegetables once a day (morning or evening) at different times e.g. dry food in the morning, vegetables in the evening. These foods should be seen as a supplement to your rabbit's main diet of hay and you will find that your rabbit is very eager to receive them, often begging like a dog. This can be hard to resist but stand firm. If your rabbit leaves any dry food or vegetables after about 20 minutes, remove them.