I don't have my paper with me here at work, but the final total to replace the nine birds (five, 7-month old laying hens, one rooster and three, 3-month old hens) came to right at $45 per bird.
This was including the cost of each day-old chick (incl. shipping, etc.), feed for the seven or three months, and the lost egg income for the five hens for one year. The total for this was $58.00 per hen. I figured this by looking up the average number of eggs a wyandotte hen would lay (200), then multiplying that by what I get per egg. I charge my customers $3.50 per dozen, which makes each egg $0.29, so that comes out to the $58.00. I did not estimate any more than one year of income per bird, because I felt like there was no guarantee that my birds would live for that long. I did look up the average lifetime laying of a chicken, which was around 700 eggs.
In my county, I would be entitled to the lost income for the entire life of each chicken, the replacement cost for each bird and replacement cost for my investment -- which would include feed, equipment and labor for building the coop, etc. I didn't feel justified in charging her that much, because she took responsibility for it in the end. She is also a college student, and I know I'd never get that much out of her, in all honesty.
I maintained asking the $35, even though my estimated total was more. She says she doen't think she can even afford that much, but I am going to allow her to make payments to me (My parents run the house she lives in, so I feel confident I will get it out of her).
Hope this helps!