we use to get field sizes like that in novice/maiden hurdles i remember when index/spread betting first came along you could easily get a 30 ish runner field at somewhere like worcester,in those days spread betting was kept pretty simple and race card numbers was a popular one the spread firms would double the numbers to get a bigger spread,back then race card numbers depended on entries so if a race had 90 entries at the 4 day stage ,and say 30 ran you could have numbers ranging from 1 to 90 so the spread could be very volatile.anyway not surprised there are some many runners at navan who wouldnt wont to run a horse there.
we use to get field sizes like that in novice/maiden hurdles i remember when index/spread betting first came along you could easily get a 30 ish runner field at somewhere like worcester,in those days spread betting was kept pretty simple and race car