So my animals are starting to get up in the higher ages and I'm just wondering at what time should I be breeding? I have started a gen 1 line for both dogs and horses. A chart would be helpful if anyone has one to share. Thanks in advance :)

Horses retire at 21 so normally people breed when they turn 20. If you want to breed twice to sell or whatever, you'd normally breed at 18 and then again at 20. For dogs, they retire at 16 so breed at 13 and 15. 

There's a little more information here about breeding details: Breeding FAQ

Thanks! I was trying to find out where I could find that information in the starter guide. Appreciate it.

Can you breed on 0 energy?? TIA  😊

 Yes, the number of shows left to train in do not affect breeding.

What Trig said! :)

Yep, and bred animals age the day of the week they're born. So some people breed them the day before their parents turn 21 (max points) or just always breed on Sundays (less to keep track of/always even with store mates)

I'm in camp #2 personally.

im team sunday. if its a meh lined animal i train for the week on sunday so i get all the entrance points and then breed
if its a private show animal I max out and leave enough room for privates 10 publics