the only 4 legged animals in fields round here are hornless cows otherwise known as horses. I seem to remember seeing cows laying down with their backs to the wind or maybe thet's a false memory.
I've often heard people say this but I don't think its true.
I believe the confusion started from a line in an old country saying "The Cattle Are Lowing It Will Bring Rain".
Lowing is another name for the sound that a cow makes when it moo's
Well it happened round my way yesterday. Drove to town around 3:00 pm and passed a field with cows in it. They were all lying down. Met office had forecast heavy rain from 4:00 pm, and this time they were spot on - almost to the minute! I've also noted that when cows lie down before rain, they tend to chose a corner of the field. At other times, they just lie down anywhere.
I've never seen a cow lie down with the legs under it, they always sort of lie half on the sides, prettu much like most herbivores. That rules the keeping legs dry reason out.