I've conducted an stress experiment in chickens. I want to compare the rate-of-change (ROC) in temperature right after a stressor was introduced, with the rate-of-change in temperature during a normal standing period of the chicken.

I have 9 chickens, so 9 observations of the rate-of-change (ROC) in temperature right after the stressor (the ROC is a relative change in temperature, so I took observations of different chickens together). I also have 30 observations of the rate-of-change (ROC) in temperature while the chickens were standing.

I am thinking to perform an ANOVA for unequal sample sizes to test if the ROC for the stressor period was different than the ROC during standing. Is this the right way to find any differences? If so, how would I implement this in SPSS for example?

Thank you.