Full spectrum light is not required to induce laying, however forcing production with improper lighting will have further negative impacts on the health of the bird. Vitamin D deficiency being the most important and common. Birds cannot properly metabolize vitamin D without sufficient UV wavelengths.
http://www.hagen.com/hari/docu/shedding_light.html
http://www.hagen.com/hari/docu/shedding_light.html