RAH, your white colored heron type is a Great Egret, Ardea alba. Several of the larger wading birds (herons, egrets, others) come in white. The GBH, Ardea herodias, as a white morph is called a Great White Heron; it's only a color phase of the more common blue variety.
Then there is the Snowy Egret. It has yellow feet. There are cattle egrets, commonly seen in groups feeding in pastures with cows. The Reddish Egret has a white morph; the Little Blue Heron also.
What indicates your bird as the Great Egret is its black legs and feet, longish thin slightly downcurved bill, and relatively large mass.
Hope this helps.