Although I've had sheep for five years what I know about them has been picked up on the way and learning from mistakes! I was first talked into getting six cade lambs which were initially intended for grass cutting; then talked into getting a ram from a sheep farmer friend as he said my ewe lambs looked like they would make good mothers (which they did!). So from knowing nothing about sheep I then got into breeding which I knew nothing about

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Anyway, apart from a hit and miss first year my Ryeland ram has produced some really excellent lambs from my ewes. I then got some purebred Charollais and they too have had fantastic lambs. From what I have read crossbred lambs usually have the hybrid vigour that purebreds don't have, for the commercial market.
I have three rams - a Ryeland, Zwartbles and Gotland. My Ryeland is used to produce lambs for market and I got the other two to breed pedigree lambs (as I have Zwartbles and Gotland ewes) but also to experiment with cross breeding.
My question is, can you cross larger sires with smaller ewes? Am I right in assuming that the smaller rams can cross with larger ewes with no problem, but would it be a bad idea, for example to cross my Zwartlbes ram (large breed) with a Gotland ewe (medium/fine breed)? I wouldn't want to risk problems for the ewe at lambing.