Last spring I lost 3 chicks from a fairly secure tractor inside my back yard, I think a teenage neighbor stole them. I set my live trap and shot a domestic cat, but didn't loose any more chicks. A few teenage chicks have flown out of my back yard and into the neighbor's where their dog got them, but that's not the neighbor's fault or anything. I clip wings but chicks are so light they do manage to escape some. I've lost a few chicks, maybe a doz, some I think overheated one day it went from being in the 60's max to being almost 90 one afternoon, a couple have escaped the brooder and got cold, had to cull one from the feed store, etc.
Last year SEVERAL roosters to raccoons and foxes before I finished securing their pen (it was an "emergency" move to a new location). After securing their pen and dispatching over 10 raccoons and 2 foxes, I didn't have too much trouble for the rest of the year. One EE hen disappeared without a trace though, and I stared padlocking the pen. One big red rooster disappeared without a trace, could have been a hawk or anything really. I lost a few free ranged roosters to the neighbor's dog, which made me really mad but they were "high risk" being free ranged. I didn't have any trouble for several more months, but now the teenage predator population is after us again.
The hens escaped their secured pen one day a few weeks back when I didn't get the gate fully latched and the neighbor's dog got two then. I started running a leg trap to catch the offending dog, but I haven't even seen him on game cam OR in their yard since May 9th so who knows. Anyways, now I have a young skunk stealing eggs inside the pen that also got one of my hens so the traps are set for it.
When I loose roosters that were destined for dinner, I loose track of their numbers. I remember at least 9 roos but there was probably a couple others. I've only lost 3 laying hens to predators (I do try to protect them a better).
I lost one cockerel to Fowl Cholera (per the necropsy) and one hen to what I think was internal laying, and one pullet that just died, maybe the heat? nothing was determined by her necropsy. Chicks and pet birds get buried near the coop, and at one point last spring I felt like I was running out of places to bury them! But it was just a rough patch, things have been better since then.