Hi Joanna,

Thank you very much for initiating this discussion on my paper. I am sorry for the delay in responding, but I am in the field and have only occasional internet access.

Yes, I agree that the trade-off is most apparent for the comparison between first and middle-laid offspring. As I mention in the paper, one reason the last-laid may seem to suffer low hatching success compared to middle laid might be due to a shift from incubation to feeding behavior once the first eggs hatch. But I do not know this with certainty. It is simply a hypothesis.

Regarding treating hatching (or laying) order as a continuous variable, in fact, I had done this in the first two submissions of the manuscript. But, after careful consideration, I changed it to a categorical variable. To make it continuous initially, I simply replaced first-, middle-, and last-hatched with the values 1, 2, and 3, respectively. However, this seemed arbitrary to me. Does being middle-hatched result in twice the effect and does being last-hatched result in three times the effect as being first-hatched? Moreover, to effectively model the inverse U-shape in the hatching order graph, I had to introduce a quadratic term. However, how does one square a value of "middle?" In the end, it seemed the conservative and sensible approach was to model it as categorical, despite the limitations you raise.