Mine have flashed every night since we put them up. It must not take a lot to charge them. We put them up in an afternoon and they were flashing that first night.
I have a goat that is limping. I can't see or feel anything wrong with her leg though. She is due to kid anytime between now and the new year. I'm hoping the limp will be gone before the kid(s) come.
The goat could have an abcess in its hoof. If the foot feels hot, that's most likely the cause. You can soak in warm epsom salt water.