At what time in their life do baby guinea pigs need not to eat Alfalfa hay?

Honestly rabbits and guinea pigs under the age of 6 months should not eat much or any alfalfa hay. Too much can kill them. It is better to give them timothy hay.Timothy hay can be used all their life or you can use alfalfa hay anytime after they are 6 months plus. Also make sure that you give them oranges for vitamin C. For the bedding you can use newspaper on the bottom of the cage with carefresh or I have always used pine or aspen bedding.