I believe you should go with the point of lay cost plus something for your trouble. Did you have any disposal or clean-up costs? This would be in addition to the trouble cost. If you go to court, you will most likely get replacement cost, not what it costs you to get and raise one to that age. I'd have the other calculation ready to show him if he balks.
Since the replace chick costs about $2 to $3 from a hatchery and they are ready to start laying at about 6 or 7 months, I'd question the other calculation. You can look at vaccinations if you got your others vaccinated and you need to consider shipping. I don't think you lost 12 months worth of eggs. I'd probably use 7 months lost. Around here, farm fresh eggs are $1.50 a dozen just down the road from me. What are they in your area? How much are organic or comparable eggs in the whole foods or natural foods store in your area?
I think you need to be careful with the calculation. As long as you can document it, it is fun to have. But if you set the cost of eggs too high, he can come up with point of lay replacement cost, subtract the value of the eggs you have already gotten and feed you fed during the time it was laying, and you may owe him money.
If all else fails, your county extension agent's office should be able to help you come up with a replacement point of lay cost.