What happens if a kitten doesn’t get sunlight?

A kitten that lacks sunlight for a long time is prone to poor bone development, because sunlight helps produce vitamin D3 and promotes calcium use. Without enough sun, the kitten may become calcium deficient, leading to stunted growth, retained baby teeth, and rickets.

Also, a dark environment harms skin health and raises the risk of ringworm, dermatitis, or mite skin disease. Many cats also become depressed without sun, showing reduced appetite, sleepiness, and inactivity, and in severe cases may develop depression.