Need statician

My data is a clinical audit. I have collected data on horses receiving intravenous fluid during 2020. I have collected data re how much they should receive and how much they actually did receive retrospectively and then improved these results the next year and collected prospectively.

I have made graphs and a box chart showing the differences and the mean and the SD etc but have been asked some questions I am not sure about. .

I am not sure what it means when it asks about the volumes being normally distributed?

These are the questions that were asked:
- were these volumes normally distributed (in which mean and SD appropriate) or not (would need to alter results)?
- he study would benefit from simple statistical analyses. This should include determining normality of distribution, comparing weight of horses in the two populations, comparing discrepancies in volumes delivered before and after implementation of change and also time spend walking horses as there seems to be a large discrepancy. This would ensure readers that described differences were indeed significant and not due to chance alone
- were these volumes normally distributed (in which mean and SD appropriate) or not (would need to alter results)
- A line in the box plots should indicate mean/median