Alfalfa is a legume hay and only suitable for pigs under 6 months or for pregnant/nursing cavies. This type of hay is used as a supplement.
Timothy hay is one variety of grass hay. Cavies must have grass hay in unlimited amounts at all times. So timothy or another type of grass hay needs to be provided.
Good pellet brands are Oxbow and Kleenmama's.
Oxbow Pet Products | Welcome and
Kleenmama's Hayloft :: Home
Hay must be given in unlimited amounts. 1 cup of veggies minimum per pig per day. Pellets can be given in unlimited amounts until about the age of 6 months then need to be limited to no more than 1/4 cup per pig per day.
Veggies and hay will provide the bulk of the Vitamin C. Pellets are the least part of the diet.
When you see white spots, it's just them expelling what their bodies don't need. Younger pigs need a bit more calcium than older pigs.
Read the sticky threads at the top of this forum. Especially the Nutrition Charts thread and the Sample menus thread. They are invaluable to many. You can also read
Guinea Lynx :: Diet.