Readigrass is richer than hay, so it’s a good idea to start him on hay as soon as you can so he gets into good eating habits while hes still very young. Readygrass is a good choice for buns that wont eat other hay, but normal hay is still the best thing. Any type of grass hay is good, really. If he’s getting junior pellets they should have enough protein and calcium needed for his growth. If you don’t have junior pellets you can give him a larger helping. Some baby buns can be free fed but some buns will pig out completely, so you need to keep an eye on that. If you can weigh him weekly and write down his weight it’s an excellent help.
THe HRS mentions 12 weeks as a suitable age for veggie-intro, unless the bun has had veg with the breeder so his tummy is already used to them. You start the introduction one veg at a time, only a small piece, watch poop for signs of tummy upset, and progress slowly as long as you don’t notice any problems.
Until veggie intro time he doesn’t need anything other than junior pellets, hay and water.