Suddenly aggressive hen

[JakesMama]

Hi everybody, I'm not sure if I'm in the right section, but a few weeks ago my sister found 6 chickens dumped in the desert by my house and I ended up adopting them. I was told to quarantine them from my other chickens on another post I had made. On chicken was very young, maybe about 4 weeks old and another had an eye infection, so I kept them separate from the other 4. The others were doing great, they were getting along just fine. They would all share the food, water and roost with no problems. Well, like typical northern Nevada weather, it recently went from mild 70's to the 90's in 2 days. When I looked out my window today, I could see some of the hens in their little yard panting heavily and acting spooked. I figured they knocked over their water and got too hot. Well, when I checked them, one of the hens had be come so aggressive that she had been attacking the other 3 chickens so bad that their back feathers were missing and they were bleeding. I noticed she was protecting the food and water and was chasing away the others. I decided to take her out of the quarantine coop and see how she would do in the main coop. One of my Leghorns quickly put her in her place and after a couple dominance scuffles, everybody calmed down and went about scratching. The other chickens she was attacking, immediately calmed down and started eating and drinking like they hadn't in weeks. I feel really bad for them because I hadn't noticed earlier
Well my question is, what would cause this one hen to become aggressive so suddenly? Could it be the heat? I don't think she and the others are old enough to be laying eggs yet (I'm still working on making nesting boxes) so I'm not sure if she may be broody or not since in the few weeks I've had them, there have been no eggs. I'm actually pretty new to raising chickens, so I'm hoping maybe someone on here might know. I checked everybody again after the sun went down and they were all roosting nicely, including the mean hen and my Leghorns. Thank you!

 

[WalkingOnSunshine]

It might have been something as simple as lack of space. You don't say how much room you gave these birds, but crowding can definitely cause the behavior you describe. Heat and lack of water would also contribute.

If it was a crowding issue, that would explain why the problem went away as soon as you removed one of the hens.

 

[JakesMama]

Well, it definitely wasn't lack of water since their little trough can hold up to a gallon and it was still pretty full when I checked it. I guess it could have been a space issue, but I was pretty sure it was big enough for all 4 of them. For their quarantine time, I have them in a 4' w x 4' l x 4' h wooden shipping crate. I put some wire on top of the crate so nothing can get in and I put the crate lid on top for some security but I have it up on some wooden blocks to keep it ventilated. I also had enough wire left over to make about the same size yard so they can go out and get some air and scratch around. They were just fine in this situation until yesterday when the temp jumped up to 90 degrees. I'm worried now because the temp is supposed to rise to 99 degrees by this Sunday!

 

[WalkingOnSunshine]

Were the birds used to more space and/or free ranging before you got them? What you have is the bare minimum for coop space (4 square feet per bird), but then most birds also get 10 sq. ft. of run space per bird. Especially if these birds were used to ranging, they are now hot and bored and their tempers are frayed. Since you've moved the offending bird, there is no use trying to do further quarantine--anything those birds had, your flock now has since you moved the one bird. Let the other three out, they'll be healthier for it.

 

[mommissan]

If the aggression continues, you could put a pinless peeper on her. It foils her attempts to attack things in front of her. I put one on my broody that would attack the rest of the flock. It made her pleasant immediately. She kept it on for months.