[Jacob-list] big lambs this year?

[Melody]

Just wondering if anyone has ever noticed a correlation between severity of winter weather and size of lambs?  We had a much milder winter than usual here, in fact we broke some high temp records in Feb. and I am having much larger lambs than usual. Not that there are any record-breaking giants, but averaging out at least a pound, probably more, higher birthweight (unfortunately my scales have decided that everything weighs exactly a pound and 3/4, so haven't been able to weigh the big boys born this morning.)  So far I have had 2 sets of twins and 3 singles (two first-timers and an older ewe) and the twins are larger than my average singles, and the singles are proportionately larger.  I've had to assist with  two of the singles and the firstborn of one set of twins, they were just too large for the ewes to birth and after prolonged hard labor I gave some help.  The twin and one single are from proven ewes who have never had to be helped--they usually pop them out like watermelon seeds. 
I can't think of what may have changed to cause this.  The first couple of big lambs I thought were just a fluke, but it is carrying through with every birth.  The sire is the same ram I have used for two previous years, and he was not a particularly large boy himself.  I have not changed feeding practices and my shearer has commented each year that my sheep are in excellent condition, neither too thin nor too fat, so I don't think overfeeding the ewes is a problem.  I don't grain them, just good hay free choice and whatever grazing they find in the pasture.  I'd sure like to figure it out, because while I don't mind larger lambs I do mind setting up a situation in which the ewes are unable to lamb unassisted.  Any ideas?  
Oh, I just thought of the only thing besides the weather that was different this year.  There was a two week period in December when I was waiting for my "hay guy" to deliver more grass hay, I ran out and they were getting an alfalfa/orchard grass mix.  Could the alfalfa for that short time have had anything to do with increased fetal growth?  
Melody at CritterLand
Redmond OR
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