Hello there and welcome to BYC!
Sounds like you are enjoying your hens!! When you free range, you run the risk of losing them to predators. You might keep your hens in an enclosed area or even use electric fencing. This keeps most critters out except the flying ones. I usually supervise my birds while they are outside. I don't leave them outside all day, just an hour or two and I keep an eye on them while they are out. Too many predators lurking and flying. When they are not outside I keep them in a predator proof run. Everything eats chicken! Raccoons can and do kill chickens so be very careful if this critter is out and about when your hens are.
As for the watery poop, it all depends. Some food can cause watery poop as can stress, over heating but so can illness, worms, coccidiosis, etc...Do they ever have solid poop or is it always watery? Have they been wormed recently? Is there any blood in the poop at all?
Feel their breast bones. Is there meat on their breasts or are they rail thin? Are they eating and drinking enough?
You might ask this question in our emergency section for more help and input....
https://www.backyardchickens.com/f/10/emergencies-diseases-injuries-and-cures
If these are fairly new birds, they should probably be wormed. Chickens are susceptible to worms if they are free ranging. Worms consume all the food the bird eats and will kill the birds over time. You can ask about this in the emergency section as well.
Good luck with your birds!! I hope they always bring you great joy! Welcome to our flock!