Rats! Rats and chickens, not my favorite duo. First of all, Hawaii has two species of rats, so I've been told by Vector Control. The roof rat and the Norway rat. The one that frequently visits my homestead is the roof rat. I've been asked a number of questions about my encounters with these rats, so I'll answer as best I can.
Do chickens attract rats? Not really, as I've been told at the ag classes that I've taken. The rats were already there before the chickens arrived. But being opportunists, the rats see a good thing and hang around more often than not. Chickens equal free food, fresh water, warm housing. They are definitely attracted by the feed. Most feeders are open buffets for rats. They will enter the coop at night, helping themselves to a free meal with no competition from the chickens. Roosters may sometimes complain about the rats, but most birds don't say a word.
Unsecured feed bins are also a rat smorgasbord. They get into feedbags, corn cribs, wooden feed bins, and even gnaw holes in plastic trashcans. They will also check out the trash bags, wild bird feeders, and compost piles. A solid metal trashcan will thwart rats.
Will a rat kill a chicken? From my own experience and what I've been told, rats didn't normally attack a full grown chicken, but occasionally they may bite them, drawing blood. The danger here is that the bird now has an open wound, which gets the attention of the other chickens who promptly peck at it. This sort of pecking can lead to cannibilism. Most chicken owners have come out in the morning and found a partially consumed bird in the pen. Not uncommon chicken behavior at all. Chickens are like having little dinosaurs, little meat eating raptors.
Rats have been known to kill and consume chicks and young birds. If the feed runs out in the feeders at night, then partially eaten young chickens might be found in the coop in the morning. A sign of rats.
Besides the problem of killing chicks and eating your expensive feed, rats can be a real problem. They will hang around and explore the area, including my barn, tool sheds, car engine, house. They can nibble wiring, foul the area with feces and urine (thus potentially spread parasites and diseases, including leptospirosis), and set up housekeeping in the walls and ceiling of the home. They contaminate stored food and water. All in all, not a suitable house guest. Some unpleasant personal experiences we've had with rats ....
.... Rat condo in our livingroom ceiling. Egads. They got into the fiberglass insulation, peeing and pooping all over it, stinking up the house We ended up having to remove the ceiling, trash all the insulation, treat the rafters, and redesign the ceiling. Expensive. Messy. Stinky. Yuk.
.... Rat vacation home inside the car engine compartment. Hubby noticed an odd rattle in the engine so took it to the repair shop. Mechanic found scores of macnuts plus loads of rat droppings under the manifold cover. An amusing story, but an expensive lesson to learn.
.... Our invisible fence system stopped working. On investigation we discovered that a rat had gnawed through the wire at the base of the control unit. It had to be replaced.
.... Rats on our roof, finding tiny niches to get into the house. No fun sitting in the livingroom one evening reading our books only to look up and see a rat walking across the ceiling beam. Yikes! Another time we woke up in the middle of the night to mad scrambling out in the hallway. One of the cats had trapped a rat but didn't know how to kill it. Our house dog was standing behind the cat, barking encouragement. Get 'em! Get 'em! The rat meantime was screaming bloody murder. Hubby felt sorry for the rat, caught it, and set it loose down in the front pasture. He said the poor thing deserved to recover from that ordeal. I wonder if it ever returned? Anyway, because of our 365 day a year rat issues (we live next door to a nut orchard), we have to be diligent in keeping the chlorine level adjusted in our water catchment tank. We collect that rainwater off the roof, which happens to be a favored venue for the rats.
What else goes wrong when rats and chickens mix? Egg theft. I don't think that I've experienced this problem, but then, the rats that visit my farm are rather small in size. I don't think they could carry off an egg if they were lucky enough to find one. I make a point of removing all eggs just before dark when the girls are already on their roosts for the night. But other people have proof that rats are stealing eggs because they've caught them doing it with their security cameras. Gotcha! They have seen rats stealing eggs right from under a brooding hen. Pretty bold, and pretty slick for a rat.