It's grammatical, but very unclear to me. In particular, the goods "will be" what?
The likely interpretation is that they will be packed, and they should be packed, but this is redundant, and the "will" subsumes the "should". It's the sort of thing we often say, thinking out the sentence as we go; but it's unclear in written text.
Edit in response to @Miloud B's comment below:
Ah! You're thinking that "will be" can be a sort of pro-verb, standing in for "arrive (later)"?
It can't. "Will" on its own can do that, or "will do", but not "will be". ("Will be" could stand for a passive verb " ... will be brought. These will be ... ")
"... the goods will arrive later. These will (do), should be packed, and will be stored in our third shed"