The Girl with All the Gifts

Didn't know this was a zombie book going into it. My biggest gripe with it is that it seems like it would be easy to clear out hungries in an area. The book already talks about how they'd dump the hungries into a lye pit to get rid of them. Why not dig a big lye pit, hang something loud and moving over the middle of it to attract the hungries, and they'd fall into it.