It is a pretty crappy breeder that would let their babies go that early

And if they opened their eyes a few days ago, then they are closer to 2 weeks old.
Babies should really stay with mom as long as possible. The very earliest they should go is 5 weeks, but 6-8 weeks is ideal IMO. I don't know any reputable breeder that would let their babies go earlier than that. IMO it is very irresponsible
Babies are usually weaned from their mom between 3-4 weeks. Most babies still nurse some up to 4 weeks. So they will likely be missing out on that and they also learn a ton of how to be a rat at that age.
Ugh it makes me angry bleh. Usually when a breeder gets rid of their babies so early they also sell eh not as pets and care more about profit then the health and wellbeing of their babies. IMO the longer they stay with their mom the stronger, healthier and far better social skills they learn for the future.
But if you are set about getting them from that breeder then there is not much you can do, besides maybe discussing with the breeder about them keeping them longer. They will be able to eat food on their own at that age most likely.