I found these LED collars handy when airing my black labs in the back pasture during these dark Montana nights.
$8 each on Amazon. Easy to customize fit with a pair of scissors.
Novkin 2-Pack LED Dog Collar, Light Up Dog Collars,Rechargeable USB, LED
We have also purchased four of them from amazon as well for our pack. As you mentioned, black labs at night on green grass makes it difficult to see everyone!
