We saw a saucer silently pass over our panicking horses and then our barn. Had alternate flashing lights a round it, blue and green

We were in the barn tending a sick foal when we heard our other horses panicking and running wildly in the pasture.  We ran outside to see what was going on and saw a saucer slowly and silently passing over our horses and then our barn.  It had alternately colored lights, blue and green I think, flashing (or pulsing?) around it. After it left the horses calmed right down.
This is one of three seemingly credible reports of overt sightings of a UFO by the same witness.  The witness indicates that the date of the sighting is approximate.  We have assigned an arbitrary date above.  PD