Fancy Grove: in my opinion that guy needs a little more training to show well at level 7. He only has heart training bars to level 6, and only one level 7 bar in strength. You can certainly try him, but I would wait if losing money on entry fees is an issue for your bank amount
Venous all the mares can be bred again on the first of every month, its called Rollover (and all horses age a year, yearly leaderboards reset etc). You can of course breed anytime assuming the mare hasn't had a foal or been used as a surrogate that year, but most people do their breeding on the 1st