Business Use Case for Livestock Product

I try to implement ERPNext to my client where they distribute chicken and duck meat. One of the biggest question is about the item Weight.

Let say they have 2 items:

  1. Chicken meat → UOM = unit
  2. Duck meat → UOM = unit

Their customer will order in “Unit” uom but for each unit, the item will has it’s own weight.

For instance, John order 100 unit of chicken meat and John asking for chicken meat that weighted 1 kg each unit.
While in the delivery process, maybe because of the long journey, there will be some weight depreciation and John will only receive 0.9 kg.

How to record this 0.1 kg that loss while in the delivery? since there is price difference between meat with 1kg weight and 0.9 weight