Harry’s ferrets
Above is shown the food I feed my ferrets as their staple diet. I have found it to be hygienic, convenient and effective. That said,  there are other makes that are of similar merit.
A ferret of 1.5 kg can be fed 80 grams of complete feed daily in two servings. This equates to a small handful morning and evening.
Top right is displayed Ferretvite, one of the various treats available, my ferrets are fond of it.
Feeding Ferrets
Links to Ferret food manufacturers.
Feeding ferrets: As stated earlier I recommended the use of a complete ferret foods specifically produced for ferrets. These foods have the correct nutrients for a balanced healthy diet and make allowance for the digestive requirements and energy needs of a ferret. Chicken or Turkey is suitable to feed them.
My earlier ferrets; I fed tinned cat food and this resulted bad teeth, diarrhoea and obesity; dog food is a worse choice. I am informed that in the  past there was common practise that ferrets would be fed a bread and milk diet, which is now known for its  poor nutritional value  and being detrimental to a ferret’s health, causing diarrhoea , accompanied by a dreadful stink. .
My friend Fred who uses ferrets to hunt rabbits prefers to feed a fur and feathers diet, which includes rabbit, day old chick alongside the more conventional beef tripe. He will feed game birds and road kills when the opportunity arises. His ferrets are fit, strong and long lived, proving the diet’s effectiveness. The  frozen day old chicks and plain beef tripe are thawed out prior to feeding. He is careful to make sure no food is left to become putrid inside the cage. He no longer feeds wood pigeon to his ferrets as it rapidly becomes rank. In the past he lost ferrets to food poisoning when they ate pigeon, they previously secreted  in the cage.  
What not to feed ferrets: Do not feed ferrets liver, hearts or red meat as this is a cause of paralysis in ferrets. Chocolate must not be fed to ferrets, it contains theobromine and  it is toxic to them. It is sensible not to give ferrets any confectionary or sugary treats, although popular with ferrets is linked to insulinoma. What is okay for humans is not necessarily healthy for ferrets.
Don’t forget ferrets drink: Water is best supplied via a gravity feed water bottle, dishes soon get up turned and fouled. The occasional treat of an equal mix of milk and water is enjoyed by ferrets. Do not give them pure milk, it is fattening and they will suffer diarrhoea.
Another point to watch is to change and wash all dishes at meal times and refill water bottles with fresh clean water.