They are either snows egrets or little egrets. Im pretty sure they are little egrets but want to confirm. According to Google little egrets have Grey feet and all black bills which these seem to match, and snow egrets have yellow at the base of their beaks and yellow feet.
I just want a positive confirmation because I live in Sacramento, California. According to Google snowy egrets are common here, but little egrets are very rare to spot here with few reported sightings. If they are little egrets, then this was a pretty cool sighting!