Need some advice from you experienced farmers! We adopted two young hens with the purpose of having fresh eggs for our tablet. They are closed at night and during the day they free range together with our two horses in their paddock (about 12000 square meters); they get along very well together at the point that of we leave the property with horses se must lock hens or they would follow us on trails. Yesterday horses were eating some hay on the ground and one hen pecked at Berta’s eye causing a small abrasion. Berta didn’t spook at all and the hen didn’t look aggressive, she just tasted the eye. Now I’m a bit worried leaving them together, do you think it is dangerous? Hens’ peck is hard and sharp I don’t want a blind horse because of and hen!
Wow, what a freak thing to happen! I also have chickens and horses, and sure would never think to worry about a hen pecking an eye! Haven’t ever had anything like that happen here, although my birds aren’t often out with the horses.
Perhaps a couple fly masks would be cheap insurance, and peace of mind?
I was there and witnessed the action! I would never think of such a thing either, I was honestly more worried about hens’ safety. Thank you Simkie, I didn’t think about fly masks, that’s absolutely an option! I’m not a chicken expert (these two are the first we have) , I was wondering maybe the hens are young (about SIX months) and she was just exploring the horse’s head with curiosity?
Chickens certainly like shiny things, and in the right light, eyeballs can be plenty shiny! Doubtful that there was any malicious intent, likely just curious 
What @Simkie said (both posts).
Especially the “shiny eye” theory.
I stopped freeranging last year after losing 2 of my (then) 5 hens to a hawk in one week.
In broad daylight, with a rooster standing guard.
Prior to that, I freeranged for 10yrs & my small flock would come down to the barn - ~300’ from their coop & fenced yard - to forage for oats, hay seed, bugs.
They also went into pastures with my horses. Never had a hen or rooster bother a horse.
What you need to think about is small predators, no threat to horses, getting to your hens.
I lost 3 to a fox in daylight, the above-mentioned hawk & loose dog injured another hen.
Like they say:
“Everything likes chicken.”
Better to fence off a yard for the hens, or let them free-range when you can keep an eye on them.
Or expect loss by attrition 
All those predators in daylight?? OMG paddock is next to our house and our dogs freerange too (they don’t bother chickens luckily) but thank you for your advice, I’ll keep hens closed when we’re not home! Luckily my husband works on shifts and I work part time so usually there’s someone to keep an eye on house and pets at least for half of the day
Did not mean to alarm you, but yes.
Fox & hawk, along with loose dogs, are your daytime threats.
Possum, raccoon, skunk & owl are the nightshift.
I don’t personally own the hens that free-range with my horses, they’re the neighbors and they hop over the fence to get at dropped feed/forage through the horse poop so I’m happy to let them enjoy my paddocks. As others have said they like shiny things. I’ve had them investigate everything shiny that comes into that paddock so I would bet the hen was just investigating a reflection in your horses eye. I keep fly masks on all my horses during the day so I would just do that to help eliminate any reflection.
In terms of predators, as I have said above these aren’t my hens so I am not responsible for their well being once they’ve hopped back over the fence. But some horses will keep an eye on them. We have a hawk that likes to circle my paddocks because the combination of hens in the yard, cats on the lanai (screened in pool deck), and a small dog in the yard several times a day is extremely tempting. The whole flock will run under the one horse when the hawk is around and if they start panic squawking that same horse will dash over and “guard” her little flock. I haven’t had a fox attempt anything yet but I have confidence that this mare would guard against it if asked to as she’s the first one to “protect” her herd anytime she thinks something is a threat.
Chicken enabler here!
I would get 2 - 4 more hens. The are social creatures and do better in larger groups.
If you free range, you will inevitably lose birds to neighborhood predators, which sometimes include your neighbor’s dogs. How much and when to free range is a delicate balance between your risk tolerance and your desire to see happy hens roaming around foraging.
My personal arithmatic on the issue is to left them out in the afternoons when we’re home. Afternoons because egg laying is usually done then and I don’t have to hunt for hidden nests. When we’re home, the dogs are outside and that is a big help, but not enough to deter a really determined fox or coyote.
The WORST time for daytime predator attack is late spring/early summer, when the foxes have kits that they’re trying to feed and teach to hunt. This is the time you’ll see foxes in broad daylight hunting.
My boarding facility has free range chickens. They have never touched the horses, in fact it’s usually the other way around. Chickens getting kicked/stepped on/run over by the horses. I wouldn’t worry about it.
My thought was maybe this horse had some yummy looking bugs right around their eye and the chicken just went to grab one…
Add me to the crowd that has chickens that free range around my horses.
That is an unusual occurrence. The only issue I have with chickens and horses being so closely kept is chicken manure in the hay( loose or baled) or feeders and the risk of the chicken being stepped on. We had that happen with a free ranging hen we had.
