I need to find replacement of incandescent light bulbs as heat-sources for my incubator. So what will be a good replacement?(reasonable acquisition)

[Kvothe]

Pay heed to the difficulties I will meet in obtaining objects that are for you within the shop next door’s reach, but are for me impossible. I need something crude, and doesn’t require the acquisition of complex materials.

 

[ChickenCanoe]

You should go with a metallic heat element. The are much more reliable and efficient than incandescent anyway. They are very straightforward. Just an L1 and L2 connection from your power source.
The wattage you choose depends on the size and insulative quality of your incubator.
Incandescents can go out at any time without warning.