We used to have an electric fence running along the bottom of our fence to keep the dogs from digging out (no longer have either dog now, one we had to put down, the other got out and never came back). Being from a rural area the only electric fence we could find at the hardware store was cattle strength. Every time I mowed after we hooked that thing up I'd find dead birds lining the fence because the fence was so powerful it killed them. My dad just told me to mow over the birds....feathers went everywhere.