Thanks for all of the great advice, everyone! What we have decided to do is to break down the costs associated with EACH individual horse being here into an itemized list, then add in the amount for the specifics of each horse (type of feed/cost per lb/amt per month)... basically, just showing our 'per horse' budget, but customizing it per horse (as opposed to saying "we feed up to 'x' amount" per feed, as we will with incoming clients). Anyhow... this has helped to reduce the amount of the increase per boarder, and hopefully will make sense to them. ANNNNNNNNNND - hopefully they'll recognize the effort we have put into trying to keep prices lower for them. I also included in the general portion of the note that, should current horse's needs change and additional feed required, it will be immediately reflected in board. Some of our boarders who have multiple horses were looking at an over $200 overall increase in board... by doing it this way, no one individual's board went up over $115 (overall).
Oh... and, after showing the "per horse" budget, we showed where (with incoming clients) the service fees (for the work we perform) will be $40.00 per horse, but we significantly reduced it for our current clients to show our appreciation for their continued loyalty. I hope it sits well and makes sense with our boarders... I think it will.