Let's take the simple bit first- water. All donkeys need access to clean water. Some people maintain that it is best to give water in buckets so you can monitor intake - but if more than one shares access I'm not sure you could tell how much each was drinking - and anyway, I personally hope that I would be able to tell something was wrong with one of mine without water intake being the only sign - but that's just my preference.
In some of my fields / stables I have automatically filled troughs etc, in others I use buckets or a trough filled with a hose - both work well.
Feed - One of the biggest problems in the UK is donkeys that are too fat, and as thier owners we must be responsible enough to limit thier intake and keep them healthy.
Too much grass can not only cause obesity, but too much grass that is too rich can cause laminits. This is a potentially serious problem leading to swelling inside the foot. With nowhere for the swelling to 'escape' to (since it is bound by the hoof) this will cause severe pain, lameness and possibly permanent changes to the structure of the foot which will mean euthanasia is the only way to give relief. My vet told me that 90% of laminitis is caused by too much food, 9% by stress and 1% they never find out - so it should be simple enough to mitigate 90% of the risk. Find out more via the button on the left.
One of the most important things to do, in my view, is to feed 'by eye' and not by any book. If your donkey looks well, and not too fat, you are probably doing it right. If it is too fat / too thin, forget what the books say about quantity and decrease / increase accordingly - they are all different. Check out the condition scoring charts on the button on the left (and by the way, I don't agree with the suggestion that 'fat' equates to 'show conidtion'. I show a great deal and would never let mine get as fat as that!).
Most adult donkeys should only need grass during the summer and good hay during the winter. (Good hay is non-dusty and has no poisonous plants such as ragwort in it). If you want to feed something additional, a handful (and I mean a handful) of pony nuts, livery mix or a specialsit food such as 'Hi-Fi Lite' could be fed - and that's probably about it. Youngsters, pregnant or lactating mares, working stallions, any elderly donkey or one in hard work will probably need more. I also tend to keep a multi-vitamin lick avaiable for all of mine so they can 'top-up' their nutrients if they feel they need it.
Do not overfeed!