Dead stock, domestic and other farm rubbish can often be appropriately disposed of into pits.
The main things to be aware of are odour and seepage.
Odour
With regard to odour, as long as only material from your own farm is disposed of in the pit, the pit is covered with a lid, a layer of soil or sawdust is added each time any offal or carcass is put in the pit, and there is no smell outside of your property boundary, you do not need a resource consent. If you cannot meet any of these requirements, you will need to apply for a resource consent (an air discharge permit).
Seepage
Seepage from pits can contain harmful materials. It is important to make sure these do not reach water. As long as the seepage does not enter streams, is well away (more than 50m) from any water supply well or spring, and is more than 25m away from a stream, you do not need a resource consent. If you cannot meet any of these requirements, you need a resource consent (a discharge permit, under the Fresh Water Plan).
REFER TO FRESH WATER PLAN FOR SEEPAGE REFER TO AIR QUALITY PLAN FOR ODOUR
Also see Burning