my neighbor and i have share a living fence, my arborvitae, 28 years old and trimmed to 8 ft and theirs a rambling yew of some sort. Over the years I've managed to keep the arbs healthy and full with deer fences in the winter but the neighbor just removed the yews and my trees are bare 4 feet from the ground up, next to where they were shaded by the over grown bushes. Is there any way I can help them fill out at the bottom? There are very few sprigs of life. Can I feed them this november so that come spring they get a boost and possibly strat new growth?

Arborvitae do have the ability to generate new buds on older wood when conditions are right. Light was likely the limiting factor while the neighbors plants were in place as you suspect. Late fall fertilization and being sure the plants receive water during dry periods will benefit the recovery. Besides the 2015 fall fertilization, you could fertilize monthly in 2016 (and future years) once growth resumes through the end of June. Consult with your local Extension Office for maximum rate in any one year based on your growing season.