Treats are a very good bonus to your hedgehogs diet. They serve two main purposes. First, they add variety to the diet. A highly nutritious diet is very important, but same old same old can get very boring. Adding variety to the diet by way of treats can help increase hedgehogs' food consumption, activity levels, and sociability. As well, it can be a nutritional benefit, depending on the quality of the treats provided.
There is no set "right" treat for hedgehogs. There is rather, a set of guidelines that you can examine food choices by to determine whether they should play a part in the treat roster.
Is the food nutritious? While a little bit of "junk food" is ok, it is strongly preferred that you choose treats that will provide some nutritional benefit over nutritionally empty fillers.
Is it safe? Sticky, very hard, or stringy foods are not a good idea for a hedgehog food, due to the potential for them to get lodged in the mouth or choked on. Some famous no-nos in this department are raisins, peanuts and many other nuts, raw carrots, and other similar items.
Is it unhealthy? Highly fatty or sugary treats are not good ideas, as well as anything that is spiced. Salt is to be avoided as well. These foods can cause intestinal upset, and in too large quantities, can cause nutritional imbalances or severe health problems.
If a food option comes up well to these rules, then it is usually worth a try.
How to feed treats is something else that needs to be considered. Treats are NOT to be the majority of the diet. They should be offered in very small quantities, a few times per week. Daily is not necessary, in my opinion, and can be negative to the overall dietary needs of the hedgehog. One or two small peices of a treat per serving is ideal, in my opinion. When you introduce a new treat, you should offer a very small amount for a few days before introducing any other new foods, to rule out any possible allergic reactions. This way, if there IS a negative reaction, you know exactly what caused it, and can make a note not to feed that food ever again.
Some commonly enjoyed human food treats to offer include cooked chicken, scrambled or boiled egg, other cooked meats, melons, strawberries, peaches, other soft fruits, peas, cooked carrots, green beans, cooked sweet potato, tomato, cottage cheese, yogurt, small peices of cheese, baby foods, baby turkey sticks, and more. Non-human foods can include wet cat foods, cat treats, ferret treats, and of course, BUGS!
Be aware that your hedgehog may be picky about what treats he prefers, so it may require trying small amounts of many different treats before you will find the ones that really make your hedgehog lick their lips. And what they don't like at one time can be offered again later, they may change their mind.