Counting sheep with Frigate

[Islautopia]

The other day, a friend of mine who lives in the countryside asked if my wonderful camera system (Frigate) could help him count the sheep coming in and out of his pen. The truth is that I don't even know if it is feasible or totally impossible to do anything halfway reliable. Has anyone solved such a problem with Frigate or have any strategies to do so? (It is necessary to take into account that sheep tend to be messy and do not always enter one by one through the gate)