I would get them one of the blocks mentioned above. However, pregnant/nursing mothers and young, growing babies need more protein. You can supplement them at home with baby food as mentioned, as well as your food. They love scrambled eggs for instance. Mine eat anything I eat (but I try and make sure their food is wholesome) like rice, potatoes, spagetti, lasagna, mine had turkey dinner over the holidays (no gravy though), ground beef, salad, chicken... They love a mixed diet just as much as we do. I always have free-choice blocks no matter what though, so they can eat whenever they want. Once they are done growing (around 3 months), it is good for them to have a low protein diet. That being said, they still love a variety. Just not so much protein.
I too feed my rats Harlan 2014. I buy the 33lb bag from FTC in Ontario and split it up and freeze it. The shipping costs more than the food! But it's still a good deal, and my rats love it.