I have 9 chickens. 4 of them are 3 years old and 5 of them are 1 year old. I've gotten all 9 from the same lady. I'm currently living in New mexico and formerly kept chickens for 8 years in Texas. This will all be relevant to my question, I promise. The first batch of chickens I got (when they were 7 weeks old), never seemed quite "right" to me. The molted a great deal more than my old chickens in Texas, had many more aggression issues, and right from the start, 3 of the 5 had egg problems (more on those in a minute). At first I put it all down to the climate in New Mexico being much harsher than Texas and the fact that these chicks had all come from a hatchery (I do remain convinced that chickens raised without a mother hen have more aggression issues). However, once the egg issues appeared in 3 out of 5 (?!!!). I began to wonder. Could this be something else? The woman I got them from said they'd all been vaccinated, but things she has said on later occasions lead me to think this may not be true. The egg issues are as follows. One chicken's eggs were always poor with weak, watery whites and shells that were occasionally misshapen. She laid an egg with a hole in it one day and died a week later. Another chicken lays eggs that are also slightly misshapen, they are long and sometimes wrinkled a bit on top. A third chicken lays eggs with paper thin shells that usually have an almost dusty crusting of calcium on them. Maybe stupidly, I bought 5 new chicks from the same woman, and again, she said they'd all been vaccinated. But it was after that that she said other things that make me think maybe she was misleading me? I thought this woman was a friend, and so I trusted her, but now I wonder if that was a mistake. Anyway, I've been pretty scrupulous about the 10% rule for treats and I feed a good, calcium fortified food (Purina Layena Plus Omega-3) and this has improved the quality of the shells in all but the paper thin eggs. The whites of the eggs are often still kind of runny though. I'm worried the big chickens have a disease they will pass to the little chickens, or, alternately, I'm worried there may be something in the dirt of our property that's unhealthy. Our property backs up onto an alfalfa field and the farmer had been putting herbicide down on the edges of the field to keep the weeds down. I asked him to stop that, and I think he did, but I can't be positive. There are trees and shrubs between the chicken pen and the field, but I worry they could be getting some herbicide residue. I'm interested in what you guys think could be going on. I don't even really feel safe eating the eggs right now. Any thoughts/advice appreciated.