I suggest you do a "Stock Addition" for the stock that you write off due to breakages or even wastages / damaged goods.
The steps would be :
1. Stock Take
2. Stock Addition
3. Select the products & enter the quantity as NEGATIVE! Eg. -15 (Remember it is meant for additions, so we need to enter a Minus to specify DEDUCTION)
4. Enter the reason eg. Damaged stock.
You can't print a total of this per month, but at least it will show as a Shrinkage & also under your stock movement detail of the items!