Racers are active during the day, so it needs to be light when you feed them and during the daylight hours. You also need to make sure your temperature is decent for them. Racers prefer hotter temperatures. Try keeping the temperature between 25 to 38 degree celcius (77 to 100 degrees farenheit). As for feeding them, newborns will take more small lizards and small frogs. The lizards they will mostly feed on when young are anoles and small skinks, and they will also take small tree frogs. Hatchlings and juvenile racers usually do refuse to eat mice, they can usually be switched over to mice when they become adults. If it's possible, try rubbing a pinkie over a small skink or anole, or even a tree frog, and then try putting it in the snakes enclosure. This will also help to switch them over to mice as they grow older. Also, when you feed them, try disturbing them as little as possible, just drop the food in and leave the snake alone, as racers are very nervous snakes and easily stressed. It's difficult with racers. They are hard to raise in captivity, but if they are captive born and they are raised properly and under the right conditions, you should have a pretty healthy snake in captivity. I hope it works out for you. Good luck.