The Growth of Lambs: Does the Number of Lambs Per Ewe Affect Their Rate of Growth?

Aim: The aim of my investigation is to see which lamb grows the best and fastest out of single, twin or triplet.
Input variable: Number of lambs per ewe.
Output variable: Growth rate (weight of lambs)
Other variables: housing, how much food for the ewe, size of ewe, the sex of it, if castrated, the breed of it.
I will make it a fair test by feeding all the ewes the same food and giving them the same amount of time out at grass. I will also keep them in the same housing environment kept at the same temperature.
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