Hickin's artistic practice initially took the form of simple, powerful sculptures created from textured, earthy materials including wood, metal, graphite, sand, copper and quartz. Resonant with what Peter Simpson calls a "spiritual humanism", Hickin's works draw heavily on the symbolism of the Christian religious tradition; in particular, his sculptures are dominated by the form of the cross. However, rather than attempting abstraction or transcendence, they remain deeply rooted in the qualities of the materials themselves, evoking a kind of spirituality inherent in the irregular grain of wood or the oily sheen of minerals.

Drawing on the writings of the Spanish Catholic priest San Juan de la Cruz (St John of the Cross), Hickin's work shifted away from sculpture towards subtle, spare compositions in graphite on white acrylic-washed board. Motifs in the form of simple geometric shapes such as doorways, crosses and horizons - and, more recently, symbols of wine - contribute to a sense of a spirituality pared back to a quietly stark, essential simplicity, reflecting Hickin's belief in "the capacity of the almost-nothing to embody the almost-everything." For David Howard, Hickin's works "inhabit - and are inhabited by - silence."