i have a beagle bitch, and have bred her twice, she didnt have her first litter until she was 3yrs.. when breeding dogs make sure that you introduce them before shoving them in a yard together, because they dont always get along at first..depending on if your bitch is in her own yard, she might feel as if it's her territory and want to defend it, but if shes in his yard she might feel scared.. she could also become jealous if you show the male too much attention.. remember that in the wild, dogs pick their own mates.. so try to be patiant with her but if it seems like shes not willing to mate with him after about a week you might have to try another male..