Agree that training/shaping is a must, and here's how I shaped our GP rescue - walk with dog ON LEASH among the chickens (one at a time in your case). Watch their behavior. If they go toward the chickens in ANY way, correct with tug on the leash and a firm NO (doesn't have to be loud to be firm) . You may need to have a more or less strong tug depending on the dog, but you MUST get their attention with the tug in order to interrupt their mindset (chase the chicken), followed by the NO. Proceed around the yard, correcting as you go. BUT ALSO - when they exhibit the correct behavior (turning away from the chicken, ignoring them when you walk past, not making eye contact with the chicken) you MUST praise/reward them extravagantly with whatever they like (hopefully they don't like chicken !!!). As they exhibit the desired behavior without needing correction let them drag the leash on the ground (so you can grab it if needed). If you have a 6-10 leash or rope you can use that would work well. Be prepared to spend whatever time is needed to get this done. One or two sessions a day per dog is likely enough. I also agree they are too young to be alone with the chickens, and definitely not a good idea for both of them, feeding off too much energy and not enough direction (shaping). Definitely too young to be without their mom if you got them at 8 weeks, but that's water under the bridge now. LGDs strongly tend to mature more slowly, partially due to their size, and also because they acquire their socialization from their parents which includes guarding behaviors. Yes, Maremmas are LGDs and they will have natural protective instincts, but the instincts must be shaped in a way that fits your situation. This is what the parents would do if given the chance. I give credit for much of this information to my friend Robert Denlinger of Kentucky.