is it muttar to watch videos of animals giving birth, or of animals mating?
We may not watch movies that bring us to have immoral thoughts. One of the examples that the Gemorah and Shulchan Aruch bring regarding not watching things that will cause us to have immoral thoughts are watching animals mating. Therefore we may not watch such a movie. Regarding watching a movie of animals giving birth, I haven’t seen anything specific on this. It would be clear though that if it would cause the person to have immoral thoughts that it would not be permitted
Tractate Avoda Zara 20b, E:H 23-3.