When people say their snake isn't eating, the first thing I look at is husbandry and security. If the snake doesn't feel safe and isn't being kept at the right temperatures, it won't eat. Baby snakes are very small and very scared of everything. Putting them in a large enclosure is not always the best decision. A small shy baby in a larger enclosure will generally give you a problem feeder.
Move to a 10g or even better, a 6 or 15qt tub. Tubs are nice for a couple of reasons. They are easy to clean, easy to regulate humidity, easy to heat, and provide a nice tight space that will make your snake feel safe.
Hides are also VERY important with a single setup (not in a rack). You want two identical tight fitting hides. This means touching the snake on all sides with one small entrance. I prefer plastic bowls from the dollar store. Cheap, effective, and easy to clean.
Contrary to what you might think, your snake does not really need any floor space. The floor space under the hides is plenty as they will spend nearly all of their time in hiding if they had the choice.
Also, you need to make sure your temps are in a good range. Those round gauges or tape thermometers are not accurate enough. You want something digital. If you have a UTH (which you should) you absolutely need a probed thermometer under the substrate right where the UTH is. You also absolutely need some way to control this heating device as it gets much to hot when just plugged into a wall. A thermostat is the best choice although a rheostat can work (and is cheaper).
Downsize your enclosure, check your temps, wait a week and then offer a live small mouse.