Some days on my way to work when I drive by a field with about 20 Gurnsey cows I see them laying down in the field, other days they are all standing. I've heard the old saying about cows laying down in the field before it is to rain, but I was wondering if there is any specific reason they lay down in the field or is this just a coincidence?

Looks like it

Most animals are vulnerable to environmental changes that humans often can't detect. Swallows flying low may indicate the air pressure is dropping. Falling pressure may affect the digestive system of cows, making them less willing to go to pasture, causing them to lie down. Static electricity may increase the grooming activities of cats. The calls of some birds, including crows and geese, have been known to be more frequent with falling pressure. Deer and elk sometimes react to wind and air pressure by coming down from mountains and seeking shelter. Some species from rabbits to rattlesnakes to certain kinds of fish may feed more before a storm so they can seek shelter.

Some flowers close up as the humidity rises so rain doesn't wash away their pollen. The leaves of some trees curl just before a storm.

Twink... I have heard that about the cows as well... not sure if it is true.

I do know that when I was growing up the old timers would predict cold weather by the different animals they saw at a specific time of the year.
They would also predict changes in weather like in the spring from a really warm period to a "cold snap" by the types of flowers, berries or trees that were in bloom or about to bloom.

I've heard something similar, that cows lie down when the pressure changes because it gives them a headache. I was young, so it could just be one of those stories you tell you kids.

Thanks for the info. It really puzzled me when I kept driving by the same field and watching some days the cows laying down (not all on some days though) and other days everyone just standing up munching away at the field cover. I tend to think it's the asmospheric pressure at work and they can sense it.

I kept honeybees in Ft. Lauderdale many years ago and I could tell when a storm was brewing as the bees would come back to the hive and hang around the hive more than usual and sure enough, a big storm would break within hours. I also had to consult the weather forecast before I would harvest the honey as the bees would get very aggressive prior to a storm approaching even if it was two days in the future. I guess the insects and animals have a better handle on the barometric pressure than we humans do after all (and they don't get the weather channel either LOL). Did not know about the flowers. That's news to me. Thanks all for the answers as I kept pondering this one for weeks.