DCAU aka DC Animated Universe had Robins and a Batgirl in it but they clearly skipped the second Robin, Jason Todd a.k.a. Red Hood. They made Tim Drake as the second Robin rather than the third. Even Tim's characteristics appeared to be an amalgam of Jason Todd's and his own.
Why did they skip him? Death doesn't seem to be a reasonable explanation, as DCAU do show deaths, such as Joker's death in Batman Beyond: Return of the Joker, as discussed here, and many more on/off screen deaths. So why did they skip Jason Todd's character?
Note 1: Looking for official answer only rather than speculation.
Note 2: Batman: Under the Red Hood is not part of DCAU.