can't say that it's worked against me, but just seems to happen that 13 is my lucky number... my first chicks last year, i wanted a dozen, got 13. first hatch from shipped eggs, 13. nearly every hatch since then has been 13 at a time it seems. (sometimes spread over a couple days but still...)
this last hatch was also 13. tho i lost one at 2 days old. now granted i have no idea how many chickens i actually have now, but i'm sure it's not a multiple of 13 (tho my sandhill chicks, i got 26 in the mail...)
i've lost a few here and there, sold some, acquired others. lost one cockerel yesterday, i think to a broken neck, tho i have no idea how. and another chick drowned in the 'pond' aka kiddie pool they all drink out of - and have been for as long as they've been outside, so no idea what happenned there. and right now my big guy's battling a systemic infection that's gone respiratory, from an abcess on his toe that ruptured (staph). so he's coughing and gurgling in the hospital cage, getting injected twice a day with penicillin.
i'm sorry you lost the baby, after the battle to save her, but sometimes i think it's for the best.
maybe after next weekend i can get an accurate head count. LOL but sometimes free ranging lots of chicks, one or two don't make it back to the house before dark and never come back. hubby calls that clorox for the gene pool. i tend to agree somewhat, even tho i'm battling to save a rooster that most would just have sent to the crockpot... he's not exceptional in any respect, except that he's my primary silver grey dorking roo. the girls don't care for junior as much right now. he hasn't learned the finesse that the big guy has i guess.
so cross fingers that the big guy starts to turn around and shows interest in food. otherwise the infection is going to win, drugs or not.