When it rains worms sometimes come out onto drive way, I take a few, 2-3, and feed them to my african brown knife, congo leaf fish and yellow lab..they love them, but is this okay?
Yeah, the main concern is chemicals they might absorb from runoff and groundwater. Depends on where your located. It's worse if there are other yards or businesses up hill from you. It's least bad if you live on high ground and no one else's water is draining towards your lawn.
Chemicals aside, earthworms are highly nutritious!
You could always throw a bag of topsoil in a rubbermaid and culture your own. It's not difficult -- the worms do all the work! Just mist with water and add corn meal!
Well my koi in my outdoor pond somehow manage to eat a few (I have no idea how they got there) and they've grown quite healthy. I've seen then having a tug-o-war with a huge earth worm once. Chasing each other like a frenzy for it.