1. Breed a bitch up to 5 times
Personally not a huge fan of this. But it also kind of depends. I don't think there's any set number of litters a bitch should have, but I don't want to see one that's pregnant all her life, either. However, better 5 than 9 or 10 (which I HAVE seen).
2. Breed 5-6 litters in some years
It depends. If I were a breeder, there's NO WAY I could handle that many pups. I probably wouldn't get a puppy from a breeder that breeds that much if for no other reason that I know that puppy was probably not well-socialized. Socialization doesn't make or break a breeder, but it's certainly nice. Logan's breeder socialized the CRAP out of him, granted he was a year old before I got him, but still. If those 5-6 litters are coming from 5-6 bitches, that is also a little different than coming from just 3 bitches. I would prefer no more than 1 or 2 litters a year. There is one bulldog breeder (miller) that has 5 or 6 litters on the ground AT ONE TIME. And this happens 3 or 4 times a year. He's by no means a good breeder, though.
On this note, my coworker got her dog from a BYB and said she liked it because they just have two dogs and bred them once to get a litter
rolleyes
and not a big breeder. When I told her Logan's dam was expecting another litter, her response was "ALREADY?!" and this was when Logan was maybe 18 months old. Um, what? Yeah, one litter every 18 months is NOT a lot. To top it off she then went and got another puppy from a breeder that is borderline mill, and when the pup didn't work out the breeder said she couldn't take it back because she just had a new litter on the ground and didn't want it contaminated (and the puppy was 7 weeks old). So, having litter like that is okay, but a second litter after a year and a half is crazy? Oooookayyyyyyy
3. Breed back to back heats (not all time time, usually just 2 litters on back to back heats, I've never seen 3)
I have heard that this may be better for the bitch, too. After we medically treat a pyometria, the vet I work for recommends the bitch is bred on the next heat cycle and then back to back and spay when they're done to prevent more pyo problems. Now, breeding a bitch back to back and getting 5 or 6 litters that way, uh, no. That seems a like a bit too much.
4. Breed 7-8 yr old bitches
Depends on the breed. A great dane? I think not. A small breed? Maybe, since some of them easily live into their late teens and 7 really isn't old at all for them.