I am Barry Thorpe from part of St. David's Poultry Team. We're the, one of the main poultry practices in the UK but I look after Scotland and we look after commercial layers in Scotland and a few backyard chickens, as well. I'm based at the vet school in Edinburgh, where we do all the post mortems and just kind of follow up work. >> So, Barry, what kind of flocks do you see here in Scotland? >> I mainly see commercial layers. They could be free range, they could be in enriched cages, they could be in barns. We have a few small producers that have a small number of birds and a few people just have backyard chickens, as well, maybe five, six, ten birds. >> And of your commercial flocks, what are the kind of size ranges? >> Hm, really, you really haven't got a commercial flock until you've got about 4 or 5,000 birds, because you just wouldn't have a good enough economic return and I've got a couple of guys, especially up north, that are almost crofters, that have about that number, about 3,4, 5,000 and they're selling into the local community bed and breakfast places, the hotels fish monger shops, that kind of thing. But the main commercial guys will have a far bigger number of birds. I look after a couple of big producers in Scotland, one that has just under two million birds and the other, probably three quarters of a million and then there's a lot of individual farmers. They're farmers growing maybe wheat or barley. They may have cattle or sheep but they put up a shed and that shed could be as small as 12,000 birds but it's more likely to be 32,000 birds and those are usually free range birds and they're supplying eggs into the main packing stations of the big producers in Scotland. >> So you obviously see a lot of free range flocks and a lot of birds, as a poultry vet what are the main issues that you see with free range egg production? >> Really the easiest way to look at free range egg production is to, you've got to compare it to something and what I compare it with would be cages and stuff, and we see more health problems in free range birds than we do in the birds in enriched cages or barns, really because they're exposed to that outside environment, which isn't cleaned and disinfected between flocks and so, they have more diseases. The other thing is, one of the advantages of a cage system is the bird is separated from its droppings. So it doesn't recycle disease. Whereas in a free range flock, or a barn, the birds are in contact with their own droppings and so a disease that's in one bird is excreted in the droppings, and that can spread to other birds, as well. So, in general, we see more health problems, E. coli Pasteurella, erysipelas in the free range birds. What about people who have the kind of free range flock where they can move their sheds from pasture to pasture. Does that greatly improve their animal health? >> Again, I've got clients that got that kind of set up. They're usually sheds that carry a load of 2 or 3,000 birds, and they tend to be the organic producers. Partly, because those smaller sized units, if they're organic, they've got a better financial return. The sheds themselves have disadvantages compared to a fixed site. It, the disadvantages include the fact that the sheds are on top of the ground and not on concrete. Therefore, they get more problems with rodents, rats and mice and that can be a real problem to keep those down and also the way those sheds are ventilated, heated, cooled, it's far more difficult to control the environment. Chickens love a temperature of about 20 degrees. At 20 degrees, they don't have to spend energy keeping warm. It's very easy for them, because originally they came from tropical type countries, so they like a warm temperature. If it drops below sort of 12, 14 degrees, it starts to get a bit chilly for them. It gets above 25 degrees, it starts to get a bit hot for them. It's very difficult in those Halo-type houses to actually keep the temperature exactly right, to control lighting, to control the environment. That's kind of an extension of the problems, part of the problems in free range. In all, in a shed, which is a barn system, there's no pop holes, the shed's closed, and you have complete control of the environment because you're controlling air in and air out. You're controlling the light intensity, you're controlling the daylight. Once you go to free range, you lose control of those parameters, because you open the pop holes, which means that, that the temperature of the shed is no longer under such close control. The day length isn't, if you're in mid-summer in Scotland, doesn't get dark until 11 o'clock at night. It's getting light again at 2 o'clock in the morning and so the birds are exposed to a longer day length. So those are some of the issues which are more of a problem to deal with in some of those small houses with 2 or 3,000 birds. >> Is the fact that they can rotate pasture significantly beneficial though because they're getting fresh pasture? >> Oh, yes, so you're going back to again, the organics. Because the organics are restricted in the use of pharmaceuticals, which includes wormers, then if they couldn't move pasture, than it would be very difficult for them to obtain worm control. What they normally do is that they'll put the pastures through a cycle, though, and they'll probably go back to the same pasture after about three years and so there is some benefit but that, but don't forget these birds are ranging and they're ranging two, three, four hundred meters. On the stages that we they have these, these houses that move, they don't move them that far, they just move them part of that distance. So you don't get absolute freedom of disease when you move the shed, you only get a partial improvement. >> You made an interesting comparison earlier, so I noticed that you mentioned that there is a difference between both free range and barn. So, apart from the outdoor exposure to pathogens, what are the significant health differences between barn and free range? >> Really, that lack of environmental control. An example would be feathering. One of, if you get a flock that's where the birds are individually pulling each other's feathers quite aggressively, if you're in a barn type situation, you have the advantage, you can reduce the light intensity within the barn, use red colored lighting, and you have complete control over that and that will normally reduce the amount of feather pulling that's going on and potentially pecking. Once you're in a free range house with pop holes, then your light control is lost to some extent as soon as you open the pop holes because you have some light coming in. >> A lot of our people who watch this kind of course will be the small backyard producer, and I suspect that most backyard producers are unlikely to put their birds in cages, because that takes away part of the enjoyment of seeing birds ranging. What kind of advice could you give them to help secure their health of their birds in that kind of environment? >> Well, I think the first thing is they've got to look at where they're actually getting their birds from and what they want to do is they probably buy in pointedly pullets from reputable dealers and birds that have been through a vaccine program and then they'll have been vaccinated for all the common poultry diseases and that would significantly reduce the likelihood of them having health problems, and if they buy in new birds, again, they want to be from reputable dealers. And then as far as the flock's concerned, their stocking density's a lot lower. Their expectations are a lot lower. If they've got ten birds and they're getting five or six eggs a day, they're probably quite happy. Whereas, if you're a commercial producer and you've got 1,000 birds, for every 1,000 birds, you're looking for between 8 to 900 eggs. So the scale of things different. The performance that's required from the birds is different and then as far as disease management is concerned, it's really good housekeeping more than anything else. You want the bird's house to be kept clean, you want to wash and disinfect it properly, at least, once a year. You want to change the bedding material, the litter material, at least, two or three times a year. You want to be dusting or spraying with some kind of insecticide to control some of the ectoparasites that might bother the birds. Probably about twice a year, you want to be worming the flock as well, so you don't get a buildup of worms. >> A lot of people that we see have got literally a backyard flock where their hens, 10, 12 hens are maybe in a fairly big backyard, so the same patch of ground is getting used over and over. Is there any thing you can do to try and reduce the parasitic load or the buildup of droppings? Well, the best thing would be, every now and again, to move them. Even if it was every couple of years. If they worm on a regular basis, that will a reduce the amount the actual ground get contaminated and then if they got if they wanted to take a few weeks out, especially if they got new birds in, then those new birds are first in the house. They could actually keep the birds, at this reasonable size house, keep them shut in for maybe five or six weeks even and during that period, they could lime the ground round the shed, and that liming would kill some of the pathogens on the surface and kill some worm eggs. >> Is there a big difference in the types of breeds of hen that people could get that are perhaps more robust, in terms of a backyard flock? Most of the breeds that are used commercially have been very heavily selected now for at least 20 or 30 years for egg production, for food efficiency, and in some ways, they probably don't lend themselves to being the best birds for a backyard situation, and if you're not particularly worried about egg numbers, then going to a traditional breeder and getting one of the more old fashioned breeds is those birds are probably a bit more robust in, in the backyard situation and probably a bit more interesting, as well. >> I want to ask you one more question, going back to the big commercial production. Something that we see that differs quite markedly between birds that are kept in cages and those that are loose housed, either in the barn where free range system is the issue of keel bone fracture. Can you tell us a little about that and what the causation might be? >> Keel bone fracture is still relatively poorly understood and there's actually currently some various studies going on trying to understand it further but it appears to be probably related to initial loss of calcium from the skeleton as the birds start producing eggs, which results in some pliability or weakness and then, as the birds are moving around their environment on and off perches and things, it's possibly sustaining some kind of injury which is causing the keel bone to be deformed or fractured. My feeling is that probably the best way to control it is to make sure that about two weeks before the birds stop producing eggs, to get them onto a proper layer diet, which has got supplementary calcium in it to give the birds every opportunity to maximize the calcium that's in their skeleton. >> And where people have small flocks and it's relatively easy to do, can they also supply an additional calcium supplement? >> Yes, very keen on that and people understand about giving grit to birds. My preference would be to use an oyster shell grit and you can also get a flint grit and the flint grit, when the birds pick it up, they keep it in their gizzard and the gizzard is, is, is, is like a muscular, very muscular stomach, and they use it in there, they move the grit around, round the grains which they're eating and that grinds up the grains, so the birds can then digest the food. They can do exactly the same with oyster shell grit and the advantage, if you got oyster grit, is the oyster shell grit is also releasing small amounts of calcium, so they're getting extra calcium, as well. So rather than buying flint grit, if they buy oyster shell grit, which would cost about the same for their backyard chickens, as far as quantities are concerned, they probably want to be putting out two to three grams per bird, per day. >> Great. Thank you very much.