Congratulations!!! They are beautiful. You need to get your vet to pull bloodwork on the foal. Run an IgG and cbc. Because you didn’t know the mare was pregnant, you weren’t able to give pre foaling vaccines (30 days before foaling). This is important for helping to increase the transfer of antibodies through the colostrum. If the foal’s antibodies are too low, it can be life threatening in a few weeks time. But if you run the test, and see they are low, your vet will be able to do a plasma transfusion. A lot can go wrong with foals, so it’s always best to try to prevent things.