Welcome! Sounds like you are doing great so far. You’ve come to a great place to get lots of information but I’ll warn you, you will also get a lot of conflicting information. A lot of that is because a lot of different things work, we are each in a unique situation so different things might work for one that won’t work for another. There is seldom just one way to do anything where other ways are wrong. They are just different. Plus we all have different experiences and opinions on things. The hardest part of getting information on this forum is to try to pick out what actually applies to your situation. Things that work with a flock of many hens and multiple roosters that free range might not work all that well if you have a flock of four hens in a small backyard coop and run.
One opinion you’ll get pretty regularly is that chicken wire is meant to keep chickens in, not predators out. It is true that some predators like a big dog or big raccoon can tear through chicken wire, depending on the gauge of the wire and how it is attached. There have been photos on here where holes have been ripped in light gauge chicken wire, usually by big dogs, so it has its risks. Still, chicken wire will provide protection against a whole lot of predators. I don’t know what you ventilation area looks like, but it’s unlikely a big dog can get to it. While raccoons can climb really well it may be difficult for them to get enough leverage to tear it. Even then, it would have to be a big enough raccoon to be able to tear it. Is your chicken wire good enough in that application? Probably.
Hardware cloth is often touted as the solution. It is usually stronger than chicken wire, depending on the gauge of the wire, but some of the light gauge hardware cloth can still be torn by a larger animal. The heavier the gauge (smaller gauge number) the more protection you get. It’s also more expensive.
In some places I use fairly light gauge hardware cloth, like fairly inaccessible ventilation areas. In other areas, like my run, I use chicken wire in conjunction with 2” x 4” welded wire. The 2x4 wire will stop anything big and the chicken wire adds a lot of extra protection and the combination is less expensive than hardware cloth. Don’t forget how it is attached is very important too.
Do you have enough ventilation? Good question. You have plenty of ventilation to guard against the ammonia risk from their decaying poop but the big issue in cold climates is getting rid of excess moisture. Excess moisture can lead to frostbite. That ventilation article in Aart’s signature would be great for you to read. The lady that wrote that lived in southern Ontario at the time so she should have a lot of credibility with you, but I think Pat went a little overboard. Part of Pat’s uniqueness was that she was trying to raise chickens and garden in a swampy area. The goal in ventilation is to move out the bad air and replace it with good air without creating breezes that hit the chickens on the roost. If you have holes high enough over their heads so any breezes created are over them, you have done well. One common way it to have openings at the top of walls under overhang to keep rain out, but there are plenty of other methods. There is hardly ever just one way to do anything. Do you need to open it up more? I don’t know. You can be preemptive and open up another hole high up on the other side. You’ll probably never know if you needed to or not. But if you start to see frostbite you have the solution.
I’m really surprised you are getting that many eggs this time of year in Ontario after moving a flock. Often people selling hens this time of year are selling older hens already in molt. They don’t lay when they are molting. Just moving them can cause a big disruption in laying. You must have gotten a bunch of pullets still in their first year of laying and they must be happy with their new digs. I said you are doing great so far! Pullets sometimes (not always but sometimes) skip the molt their first fall/winter and keep laying through. But expect an almost total shutdown next fall/winter because they will molt under normal circumstances at that age.
Often when a pullet first starts to lay you will find strange eggs, like soft shell, no shell, extremely hard shell, double yolked eggs, eggs with no yolk or no white, all kinds of strange things. The hen’s internal egg making factory is fairly complicated, it’s not that unusual for it to take a week or two for her to work all the kinks out of the system. Also, some pullet seem to have no control over laying their first few eggs. They might drop them anywhere, walking around or from the roosts. But once they gain control of the process, they look for a safe place to lay and that becomes their nest. If they are laying in the same place every day, that is their nest. In both of these, laying good eggs and having control of the process, most get it right to start with, but several don’t.
Are you feeding that oyster shell separately or mixed with their other food? Laying pullets and hens need excess calcium for their egg shells that non-laying chickens don’t need. If you offer the oyster shells on the side most hens instinctively seem to know they need it and will eat enough. The ones that don’t need it shouldn’t eat enough to harm themselves. A lack of calcium might explain the soft shelled eggs. The Layer feed should contain enough calcium for egg shells if that is all they are eating, but you are providing other stuff. It is not about how much calcium is in one bite, it’s about how much total calcium they eat daily. You may be watering down the total calcium with all that other stuff. If you are not already doing so, try offering the oyster shell on the side and see if that helps. If it doesn’t maybe cut back on some of that other stuff. Even in Ontario this time of year, they are probably foraging for a lot of their food anyway so you don’t have total control of their entire diet.
The hen’s internal egg making factory is fairly complicated. It’s not unusual to have an occasional glitch. An occasional soft shelled egg is not a big reason for concern. It’s when soft shells are regular you need to try to solve a problem.
When I have a problem I try to look at it as a flock problem or an individual chicken problem. If it is a common flock problem I try to treat the entire flock. If it is an individual problem, I tend to treat the individual. Some hens regularly lay soft-shelled eggs. There is something wrong with her body so she does not process the calcium right or her instincts don’t work right so she doesn’t know to eat enough calcium. This is pretty rare but not totally unheard of. Too much calcium can be hard on the hens that do process it right. Some of this stuff is not always easy.
I’m pretty laid back on the roosts. I’ve found that chickens can do quite well on 2x4’s either flat or on end, tree limbs, or flat shelves. Some people have strong opinions on all these but I don’t. I do want the roosts made of wood during winter especially. I do have an opinion on that. Some roost materials like metal or plastics can conduct heat really well. That can lead to frostbite of the feet if they are roosting on them and the weather is below freezing.
There are two reasons I think most people should have roosts. Some chickens like some Silkies don’t fly and some of those don’t roost, though some do. But most chickens like to sleep on the highest thing available. The pecking order determines who gets the choicest spots, but you can help keep them from sleeping in your nests if you use roosts correctly. Put the roosts higher than anywhere you don’t want them to spend the night. Some chickens can get fairly brutal on the roosts as they are settling down for the night. Some chickens are just bullies, that’s the way they are. Usually if they are all mature it’s not a big deal, but it can get pretty wild on the roosts if you have different aged chickens. Even with adults I find the ones higher in the pecking order sleep in one area and the ones lower down sleep in the far corner. I don’t go by X number of inches per chicken on the roosts but try to give them enough room for the weak to avoid the bullies if that is a problem.
The other reason for roosts is poop management. You may have noticed they poop a lot all the time. At night they are not moving around so that poop can build up. That’s why you don’t want them sleeping in the nests, who wants poopy eggs? Since the poop builds up so much where they sleep, you can use the roosts to help manage the poop. Aart gave some of the benefits, but if you have a collection system (droppings board or bins) under the roosts you can get a lot of poop out of your coop and into your compost where it belongs.
Chickens do a lot of things by instinct but they are intelligent enough they can be taught. Either self-taught or you can teach them. It’s not always easy but it can be done if you are patient and consistent. When a hen decides “this is my nest” her instinct is to lay in that spot every time. You can retrain them though, if you want to. If the eggs are clean, relatively predator safe, and you are willing to retrieve them, does it really matter where the nest is? Not to me, but I’m not real young. Ease of retrieving them is important to me. They don’t always pick real clean spots either.
If you are unhappy where they are laying, there are a few things you can try. Since yours are laying in the coop, it won’t help to confine them to the coop or coop and run until they lay their egg. That’s one trick I’ve used if they are laying in nests outside somewhere.
Some people say to mess up where they are laying or to put something there to block it. That’s never worked for me. They just lay next to whatever I put there. Maybe I’m not doing it right.
They often like to lay where another hen is laying, maybe they think that makes it a safe nest. Putting fake eggs in the nests often entices them to lay there. I use golf balls but ceramic or wooden eggs or even plastic Easter eggs might work. For bantams some people use ping pong balls. Does this always work? Of course not. One poster said their hens refused to use the nests until they took the fake eggs out. I find if I don’t keep the golf balls in my nests they tend to lay other places.
That’s another point, don’t expect chickens to be consistent. No matter what anyone writes on here, someone can come up with an exception. We can tell you what our chickens normally do but I often see exceptions to what I write in my own flock. They are living animals, you need to be flexible.
One method I have not tried but people I trust said it works is to put a portable nest where they are laying, maybe a cardboard box with nesting material and a fake egg. Once they have started using that nest regularly, slowly, a foot or so at a time, move it to the nest area you want them to use. When you get them to the area your nest is in, remove that box and see if they make the switch the way you want them to. Or just use that box as your permanent nest.
I made some of my nests so I can lock a chicken in them if I want to. When I have a hen laying where I don’t want her to I catch her and lock her in a nest. After she lays her egg I let her out. It normally takes a half hour or so, but I had one hen that took over three hours. Usually it only takes me once doing this, but that hen that took three hours was stubborn. I had to lock her up the next day too before she learned.
This is way too much typing this morning so I’ll quit. You are off to a great start. Good luck the rest of the way.