That's the question I am trying to answer for myself. This year I tried my first ever broilers and a few BBB turkeys. I wanted to buy heritage breeds but couldn't find a hatchery that would sell only 5 heritage poults.
There is no doubt that broilers are easy and fast. My Cornish X's are close to 2 months old and are ready for the freezer. All they care about is food and water, they don't demand my attention and don't peep like the world has ended if I leave them. In fact, they don't care if I leave them as long as they have food and water. So far, I have not lost any. I got 26 from McMurry, a mix of Cornish X's, Red Rangers and Pioneers. Red Rangers will take a bit longer and Pioneers even longer judging by their size, but by 4 months I think they will all be in the freezer.
My BBB turkeys took forever to learn to eat though I put them with chickens, they would only eat from my hands for a while. I came close to losing one of them (I have 6), and had no idea what was wrong with it. As a last ditch attempt I gave it some antibiotic when I thought it would die overnight and by the morning it was doing a lot better and that's about when I figured out what was wrong with it. Turkeys can be extremely annoying (or adorable, depending on how you look at it), they won't shut up if I leave them for a moment. They think I am their mom and would only go about their business (like eat, drink, forage or dust bathe) if I am around, otherwise they would be running along the wall of their tractor or a fence testing it to see if they can get out peeping incessantly. I definitely spent a whole lot more time caring for my 6 turkeys than for my 26 broilers, a bunch of laying hens and more laying hen chicks that I am raising now. And the worst part is that I can't imagine dispatching them since they have almost become like kids, they are so needy and always like to be around you and jump on you and what not. Yet, we'll have to cross that threshold soon enough because, as far as I understand, you can't successfully breed broad-breasted turkeys.
Now, why am I still considering raising turkeys in the future (and I am only comparing chickens and turkeys here since I don't have any experience with any other poultry)? I care a lot about the quality of my food. Since, we are what we eat, our food is what they eat. The best quality can only come from free-range birds that consume as much grass and insects as possible. It doesn't matter how much grass you give your free-range chickens they don't care much for it. Given choice between grass and grain broilers will always choose grain. They jump onto their feeder in the morning grunting like little pigs, pretty disgusting, but that's what they are bred to do. Even though I free-range my broilers in a tractor that I move several times a day, they at best consume 5% of their feed from the grass. Their meat is still superior to any Tyson or even organic chickens. We just tried our first broiler last weekend and it was like a completely different bird compared to store-bought chickens and still, they are at least 95% grain-fed.
My BBB turkeys spend most of their time foraging. They would come up to their feeder a few times a day and would go back to eating grass. I can't measure % of their grass but I think it can be easily anywhere from 30% to 50% and I think heritage varieties would do even better if given access to pasture. I really wish they were less needy and more robust when they are poults because they seem to get sick from everything and anything imaginable and unimaginable, however, I believe in terms of meat quality (or egg quality if you can get any eggs from them) a free-range turkey is definitely superior to a free-range broiler-chicken. If they do not free-range and only have access to grain, then really there will be no difference.
