Okay I couldn't find any info on feeding baby achatina so did a little trial and error. I found the baby achatine will birth at around 500 food. At first it would not let me put anything into the inventory. At about 100 food I was able to put a sweet cake into it. It did not eat it until about 25 food. Once it ate it was back up to 500 food. Does not feed off of the maewing as of yet. So far seems like it must be hand fed.