IN MY PERSONAL OPINION AND THAT OF MANY TOP CHINCHILLA BREEDERS AND PET OWNERS, YOU SHOULD NOT feed mixes such as Charlie Chinchilla or XtraVital (these look like rabbit mixtures). The animals will pick at the food and eat the items that they like and leave the pellets where the balanced nutrition and minerals that have been researched have been placed. Feeding these types of products can often lead to tooth disorders over prolonged periods of time as the animals east all the 'treaty' items that it contains and leave the harder pellets which help to create the required dental wear.
For treats - only provide sparingly and infrequently. Chinchillas have a very easily upset digestive system. Avoid fresh fruits, nuts, sugared or fatty items - and be sparing with the raisins. Good treats include pumpkin seeds, mini shredded wheat, small pieces of apple (one piece a week), tea spoon of 'luxury' mixes like Charlie Chinchilla or dried apple leaves
Treats should be limited to one a day eg one raisin. Incorrect diet or too many treats will lead to dental problems. Their teeth grow all the time and are dependent on pellets and hay for correct grinding to keep them in shape and the right length. Gnawing on wood will keep the incisors at the front of the mouth in shape - but have no effect on the molars at the back of the mouth which can on an incorrect diet can overgrow and lead to a chin unable to feed itself and requiring veterinary assistance - it can at times also lead to the death of the animal
Chinchillas can cope in low temperatures, but do not cope well with warmer weather - being kept at temperatures of over 85 degrees F can lead to death - so it is important to ensure that the chinchillas in times of hot weather are sufficiently cooled. This can be done by a variety of methods including fans, ice and frozen treats.