This is a pack of six cobs:
1. Identical Twins: The norns will produce genetically identical twins!
2. "Fraternal" Twins. Same as above except egg colour and sex are potentially different.
3. Brood Size Determinator. Norns will vary the size of the brood depending on how crowded they are. Less crowded means more eggs up to a maximum of five. Useful for feral runs to help ensure a stable population. (For many animals brood size is a function of the availability of resources).
4. Livebearing. Bypasses egg stage. Avoid the viccissitudes of eggs. If it works for higher animals it will work for your norns.
5. Livebearing Identical Twins.
6. Livebearing Brood Size Determinator. This is the most useful Cob of the six for feral runs and for seeing evolution in action.