I had two litter sisters both 18 1/4” tts one was lighter framed than the other& faster. Both good ferreting, mouching & lamping dogs. Worked them as a pair doubled up & they caught well above their pay grade. Caught there first rbt at 4 1/2 months old & never looked back. Bought them as 3/4 whpt 1/4 beddy but they were actually 5/8 3/8. Had to have lighter framed one pts 16mths ago & the heavier built one worked ok on her own but not the same as when doubled up. She’s now retired but enjoys her daily walks mouching etc but 9 &1/2 now & like her owner overweight.