To substitute whole or ground, use a 1:1 ratio. To sub a chia egg for a flax egg, mix 1 tablespoon of ground chia seeds with 3 tablespoons of water and let it sit for a few minutes until it thickens.
Not only has consumer demand for flaxseed grown, agricultural use has also increased. Flaxseed is what's used to feed all those chickens that are laying eggs with higher levels of omega-3 fatty acids.