Put all ingredients in a large pot and cover with water till the bones are 2-3 inches under water.Bring to a simmer then reduce heat so that it stays at a very gently simmer. You don't want it to boil as it will make the stock look dirty. It won't effect the taste but it won't look as nice and clear.Continue to simmer gently, uncovered, for about 4 hours.Remove from heat and strain though a colander into a large bowl. Place a fine mesh sieve over another bowl and strain once more to remove any small particles. Season to taste with sea salt.Store in covered containers in your fridge for up to 3 days or freeze for longer storage*