Alpaca Breeding Record and Birth Calendar  
 
Here is an MS Excel spreadsheet that covers any year and gestation period.
Download it and use it.
It is setup for the breeding record on one side and a birth gestation calendar on the other.
Fill in the items at the top, change the gestation period and the year, and the spreadsheet automatically fills in all the other fields. Print one for every bred female on a duplex printer.