Timothy is the primary hay you will feed your chinchilla. Hay should be available to your chinchilla at all times. Sweet Meadow, Orchard Grass and Brome hays are also choices that can be given to your chin to add occasional variety.
Alfalfa is a sweeter hay and chins love it, but it should be given only as a treat past the age of one year old. It can cause soft poops for some adult chins if fed in excess. Also, Alfalfa hay is higher in calcium than Timothy hay and it has been linked to possibly causing excessive calcium in the diet and therefore contributing to bladder stones. The extra calcium is why Alfalfa is often given to pregnant chins who risk having their calcium depleted during pregnancy and when nursing newborns. Alfalfa is also good if you have a chin that is ill or weak and will not eat. Often the sweeter and leafy Alfalfa hay will encourage them to eat again on their own. Once he feels better, you can go back to feeding only the Timothy hay.
Hay should smell fresh and appetizing. Do not ever give your chin hay that smells dusty, wet or moldy in any way! There should be no sticks or weeds in the hay. Quality will matter whether your chin will even eat the hay or not. Once again we believe Oxbow Timothy Hay to be the best you can give your chin. Store your hay in a cool dry area.
These should be given to your chin as a treat or chew toy and NOT their primary source of hay. A hay cake is not the same as giving your chin loose hay. Hay cakes are much drier and made of chopped small pieces, whereas loose hay has 'moisture' and long strands that really work your chin's molars. Hay cakes are great to help wear down your chin's teeth to a healthy length and are a stimulating chew toy that chins love to carry around the cage with them. You can find hay cakes made with timothy, alfalfa and sometimes a mix of timothy and alfalfa hays.